The spinal cord of an adult. How the human spinal cord is arranged: structure and functions than a gray substance is formed

Anatomy of the nervous system

The nervous system regulates the activities of all organs and systems, caused by their functional unity, and provides the connection of the body as a whole with an external environment. The structural unit of the nervous system is the nervous cell with process - neuron. The nervous system is a totality of neurons that contact each other with special devices - synapses. According to the structure and function distinguish three types of neurons:

Receptor, or sensitive (afferent);

Insert, circular (conductor);

Effective, motor neurons, from which the impulse goes to the working bodies (muscles, glands).

The nervous system is conventionally divided into two large departments - somatic, or animal, nervous system and a vegetative, or autonomous, nervous system. The somatic nervous system makes predominantly the body's communication function with an external environment, providing sensitivity and movement, causing a reduction in skeletal muscles. Since the functions of movement and feelings are characteristic of animals and distinguish them from plants, this part of the nervous system has been named animal (animal).

The vegetative nervous system has an impact on the processes of so-called plant life, common to animals and plants (metabolism, breathing, isolation, etc.), which is why its name (vegetative - vegetable) occurs. Both systems are closely related to each other, but the vegetative nervous system has some degree of independence and does not depend on our will, as a result of which it is also called the autonomous nervous system. It is divided into two parts sympathetic and parasympathetic.

In the nervous system, the central part is the head and spinal cord - the central nervous system and the peripheral, represented by the nerves derived from the head and spinal cord, is the peripheral nervous system. On the cut of the brain it can be seen that it consists of gray and white substance.

The gray substance is formed by the accumulations of nerve cells (with initial departments derived from their bodies of processes). Separate limited accumulations of the gray substance are nuclear names.

The white substance form nerve fibers coated with myelin shell (the processes of nerve cells forming a gray substance). Nervous fibers in the head and spinal cord form conductive paths.

Peripheral nerves depending on which fibers (sensitive or motor) they consist, divided into sensitive, motor and mixed. The bodies of neurons whose processes are sensitive nerves lie in the nerve nodes outside the brain. The bodies of motor neurons lie in the front horns of the spinal cord or motor kernels of the brain.

The central nervous system perceives the afferent (sensitive) information arising from the irritation of specific receptors and in response to this forms the corresponding efferent impulses, causing changes in the activities of certain organs and organism systems.

The anatomy of the spinal cord

The spinal cord lies in the spine channel and is a 61-cm litter length - 45 cm (in an adult), a somewhat flattened front. At the top it directly goes into the brain, and at the bottom ends with a sharp cone - at the level II of the lumbar vertebra. From the brain cone down, the terminal thread is departed, which is an atrophied lower part of the spinal cord. At first, on the II month of intrauterine life, the spinal cord occupies the entire vertebral channel, and then due to the faster growth of the spine lags behind and moves upwards.

The spinal cord has two thickening: cervical and lumbar, corresponding to sites from it from the nerves going to the upper and lower limbs. The anterior median gap and the rear median groove of the spinal cord is divided into two symmetrical half, each in turn has two low-rise longitudinal grooves, from which the front and rear roots are the spinal nerves. These furrows share every half of the three longitudinal tights - the rope: front, side and rear. In the lumbar area, the roots go parallel to the end threads and form a bunch, which is called a horse-tail.

The inner structure of the spinal cord. The spinal cord consists of gray and white substance. The gray substance is laid inside and from all sides is surrounded by white. In each of the half of the spinal cord, it forms two irregular shape of vertical heavy tape with the front and rear speakers - the pillars connected by the jumper - the central intermediate substance, in the middle of which the central channel passes along the spinal cord and containing the spinal fluid. In the thoracic and upper lumbar departments there are also side protrusions of the gray matter.

Thus, in the spinal cord there are three paired column of gray matter: the front, side and rear, which are called the front, side and rear horns on the cross section of the spinal cord. The front rog has a rounded or quadrangular shape and contains cells giving rise to the front (motor) spinal cord roots. The rear horn is already longer and includes cells to which the sensitive fibers of the rear roots are suitable. The side horn forms a small triangular shape of the protrusion consisting of cells relating to the vegetative part of the nervous system.

The white plate of the spinal cord is the front, side and rear core and formed predominantly longitudinous nerve fibers combined into bundles - conducting ways. Among them there are three main types:

Fibers connecting the areas of the spinal cord at different levels;

Motor (descendingable) fibers that come from a brain in a spinal connection with cells that start the front motor roofs;

Sensitive (ascending) fibers, which are partially a continuation of the fibers of the rear roots, partly by the process of the spinal cord cells and go back up to the brain.

From the spinal cord, forming the front and rear roots, 31 pair of mixed spinal nerves departs: 8 pairs of cervical, 12 bedroom pairs, 5 pairs of lumbar, 5 pairs of sacral and 1 pair of cleaners. The area of \u200b\u200bthe spinal cord, corresponding to the dishevement of the pair of cerebrospinal nerve, is called the spinal cord segment. In the spinal cord there are 31 segments.

Anatomy of the brain

Figure: 1 - finite brain; 2 - intermediate brain; 3 - medium brain; 4 - bridge; 5 - cerebellum (rear brain); 6 - spinal cord.

The brain is located in the skull cavity. Its upper surface is convex, and the bottom surface is the base of the brain - thickened and uneven. In the base of the base from the brain, 12 pairs of cranial (or cranic and brain) nerves are departed. The brain differences the hemisphere of a large brain (the most new in evolutionary development is part) and a barrel with a cerebellum. The mass of the adult brain is average equal to men 1375 g, in women 1245. The brain mass of a newborn brain on average 330 - 340 g. In the embryonic period and in the first years of life, the brain is intensively growing, but only by 20 years reaches the final value. [...]

Anatomy of the oblong brain

The boundary between the spinal and oblong brain is the place of the reserves of the first cervical spinal nerves. At the top it goes into a cerebral bridge, its lateral departments continue to the lower legs of the cerebellum. On the front (ventral) surface, two longitudinal elevations are visible - the pyramids and the false duck from them olives. On the rear surface on the sides of the rear median furrows, thin and wedge-shaped rods, which continue here from the spinal cord and ending with the cells of the same name, forming thin and wedge-shaped tuberculos on the surfaces. Inside olives are the accumulation of the gray substance - the olter core.

In the oblong brain there are the kernels of the IX-XII pairs of cranial (cunning) nerves, which go on the lower surface behind the Oliva and between Oliva and the pyramid. Mesh (reticular) The formation of the oblong brain consists of weave the nerve fibers and the nerve cells that are between them forming the reticular formation kernels.

Figure: Front surfaces of the frontal fraction of a large brain hemispheres, intermediate and medium brain, bridge and an oblong brain. III-XII - appropriate pairs of cranial nerves

Figure: Brain - Sagittal section

White substance form long fibers, passing here from the spinal cord or heading in the spinal cord, and short, binding the cores of the brain stem. Between the cores of Olive is the crossroads of nerve fibers, originate from the cells of the thin and wedge-shaped nuclei.

Anatomy of the back of the brain

The brain bridge and cerebellum include the brain bridge: it develops from the fourth brain bubble.

In the front (ventral) part of the bridge, the accumulations of the gray substance are located - its own nuclei of the bridge, in the rear (dorsal) part of its parts lie kernel of the upper olive, the reticular formation and the kernel V - VIII pairs of cranial nerves. These nerves come out on the base of the brain on the side from the bridge and behind it on the border with the cerebellar and the oblong brain. The white substance of the bridge in its front part (base) is represented by transversely walking fibers heading into the middle legs of the cerebellum. They are permeated with powerful longitudinal beams of the fibers of the pyramidal paths, which then form the pyramids of the oblong brain and heading in the spinal cord. In the back (tires) pass upward and downstream systems of fibers.

Figure: brain barrel and cerebellum; side view

Cerebellum

The cerebellum is preserved from the bridge and the oblong brain. It highlights two hemispheres and the middle part - the worm. The cerebellum surface is covered with a layer of gray substance (cerebeller bark) and forms narrow winding, separated by furrows. With their help, the cerebellum surface is divided into slices. The central part of the cerebellum consists of a white substance, in which the accumulation of the gray substance is laid - the cerebellum kernels. The largest of them is a gentle core. The cerebellum is associated with a brain barrel with three pairs of legs: the top join it with the middle brain, medium - with the bridge and the bottom - with the oblong brain. They pass bunches of fibers connecting the cerebellum with different parts of the head and spinal cord.

The rhombid cerebral changes in the process of development make up the boundary between the rear and middle brain. From it develops the upper legs of the cerebellum, located between them the upper (front) brain sail and the triangles of the loop lying in the duck from the upper legs of the cerebellum.

The fourth ventricle in the development process is the residue of the rhombid cerebulism cavity and is thus the cavity of the oblong and rear brain. At the bottom of the ventricle, it is reported to the central channel of the spinal cord, at the top proceeds in the medium brain cerebral water supply, and in the roof area it is connected with three holes with subarachnoid (subpautented) brain space. The front (ventral) wall of it is the bottom of the IV ventricle - is called a diamondy straw, the lower part of which is formed by the oblong brain, and the top - the bridge and the cereal. The rear (dorsal) - the roof of the IV ventricle - is formed by the upper and lower brain sails and is supplemented with a planing of a soft shell of the brain lined with ependa. In this area there is a large number of blood vessels and vascular plexus IV ventricular are formed. The place of convergence of the upper and lower sails goes into the cerebellum and forms a tent. The rhombid fossa is vital, as in this area most of the cranial nerve nuclei (V - XII pairs) are laid.

Anatomy of the mid-brain

The medium brain includes the legs of the brain, the location, ventral (kepened) and the roof plate, or quadruple. The cavity of the midbrain is the brain water supply (Silviev plumbing). The roof plate consists of two upper, and two lower hills (tubercles), in which the cores of the gray substance are laid. The upper hills are associated with a visual basis, the lower - with the auditory.

From them originates the motorway going to the cells of the front horns of the spinal cord. Three of its departments are clearly visible on the vertical section of the mid brain: the roof, tire and base, or the brain leg itself. Between the tire and the base is a black substance. In the tire lie two large kernels - the red nuclei and the kernel of the reticular formation. The brain water supply is surrounded by a central gray substance in which the core of the III and IV pairs of cranial nerves lie.

The base of the brain legs is formed by the fibers of the pyramid paths and paths connecting the bark of large hemispheres with the bridge cores and the cerebellum. The tire contains the rising paths that form a bundle called medial (sensitive) loop. The fibers of the medial loop begins in the oblong brain from the cells of the cores of thin and wedge-shaped cords and end in the cores of the visual bulb.

The lateral (auditory) loop consists of a hearing pathway fibers coming from the area of \u200b\u200bthe bridge to the Lower Hollochoms of Thoroughly and the Medial Crankshaft of the Intermediate Brain.

Anatomy of intermediate brain

The intermediate brain is located under the corpulent body and the arch, firing on the sides with the hemispheres of the big brain. It includes: Talamus (visual bumps), epitulamus (supervisory region), metatalamus (Zabigorny region) and hypothalamus (subbojorny region). The cavity of the intermediate brain is the III ventricle.

Talamus is a paired gray substance clusters, coated with a layer of white substance having an ovoid shape. The front department adjoins it to the interventricular opening, the rear, extended, - to quadruple. The lateral surface of the Talamus is growing with hemispheres and borders with a taper core and an inner capsule. Medial surfaces form walls III ventricle. Lower continues in the hypothalamus. In Talamus, there are three main nuclei groups: front, lateral and medial. In the lateral nuclei, all sensitive ways are shifted to the crust of large hemispheres. The epitulamus is the upper appendage of the brain - the epiphysis, or a sishkovoid body, suspended on two leashes in the recess between the upper hills of the roof plate. Metatalamus is represented by media and lateral crankshafts connected by bunches of fibers (knobs of hollochika) with top (lateral) and lower (medial) roof plates. They are kernels, which are reflex centers of vision and hearing.

The hypothalamus is located a centrally visual building and includes a proper subbozhny region and a number of formations located on the basis of the brain. These include; The final plate, the visual crossover, the gray borger, a funnel with a lower gifting of the brain derived from it - the pituitary gland and the deputy bodies. In the hypothalamic region, kernels are located (supervisory, surrounding and other), containing large nerve cells that can allocate the secret (neurospecret) entering their axons into the rear part of the pituitary gland and then into the blood. In the backyard of the hypothalamus, the kernels formed by small nerve cells are lying, which are associated with the front fraction of the pituitary of the special system of blood vessels.

The third ventricle is located in the midline and is a narrow vertical slot. The side walls are formed by visual shoots and a subbormal region, anterior - pillars of the arch and anterior spike, the lower - the formations of the hypothalamus and the rear-legs - the legs of the brain and the protzorous region. The upper wall is the roof of the ventricular roof, is the thinnest and consists of a soft (vascular) brain shell, lined by the ventricular cavity by the epithelial plate (ependym). From here to the cavity of the ventricle is pressed a large number of blood vessels: and vascular plexus is formed. In front of the III of the ventricle reported with side ventricles (I and II) with interventricular holes, and the rear moves into the brain water supply.

Figure: Brain barrel, top view and rear

Holding head and spinal cord

Systems of nerve fibers conducted impulses from skin and mucous membranes, internal organs and organs of movement to various parts of the spine and brain, in particular to the core of a large brain hemispheres are called ascending, or sensitive, afferent, conductive paths. Systems of nerve fibers transmitting pulses from the bark or underlying brain cores through the spinal cord to the working body (muscle, iron, etc.) are called motor, or descending, efferent, conductive paths.

Conductive paths are formed by chains of neurons, and sensitive pathways usually consist of three neurons, and motor-from two. The first neuron of all sensitive paths is always out of the brain, being in the spinal nodes or sensitive hubs of the cranial nerves. The last neuron of motor tracks is always represented by the cells of the front horns of the spinal cord or the cells of the motor core nerve nuclei.

Sensitive ways. The spinal cord conducts four types of sensitivity: tactile (feeling of touch and pressure), temperature, pain and proprioceptive (from muscle receptors and tendons, so-called articular and muscular feeling, feeling of position and movement of the body and limbs).

The bulk of the upstream paths conducts propriceceptive sensitivity. This indicates the importance of controlling movements, the so-called feedback, for the motor function of the body. The path of pain and temperature sensitivity is the lateral spinatelamic path. The first neuron of this path is the cells of the cerebrospinal nodes. The peripheral processes are part of the spinal nerves. The central processes form the rear roots and go in the spinal cord, ending on the cells of the rear horns (2nd neuron).

The processes of the second neurons through the spinal cord commissation are transferred to the opposite direction (form the cross) and rise in the side rope of the spinal cord into the oblongable brain. There they are adjacent to the medial sensitive loop and go through the oblongable brain, the bridge and the legs of the brain to the lateral kernel of the Talamus, where they switch to the 3rd neuron. The thalamus nuclei cells are formed by a tamlamocortic bundle passing through the back leg of the inner capsule to the core of the post-central winding (the area of \u200b\u200bthe sensitive analyzer). As a result of the fact that the fibers on the way are crossed, pulses from the left half of the body and limbs are transmitted to the right hemisphere, and on the right half - to the left.

The front spinctalamic path consists of fibers conducted by tactile sensitivity, it passes in the front rope of the spinal cord.

The pathways of the muscular and articular (proprioceptive) sensitivity are directed towards the core of the hemispheres of the big brain and in the cerebellum, which participates in coordination of movements. Two spin-plated paths go to the cerebellum - front and rear. The rear backing path (Flexiga) begins on the cage of the spinal assembly (1st neuron). The peripheral protempted is part of the spinal nerve and ends with a receptor in the muscle, the drain capsule or bundles.

The central process in the rear root is included in the spinal cord and ends in the core cells located at the base of the rear horns (2nd Neuron). The results of the second neurons rise in the dorsal part of the side rope of the same side and through the lower legs of the cerebellum go to the cells of the cerebel cerebral cortex. The fibers of the front spin coach (Govers) form the cross twice; In the spinal cord and in the region of the upper sail, and then through the top legs of the cerebellum reach the cells of the cerebel bark.

The propriceceptive path to the crust of large hemispheres is shown in two beams: gentle (thin) and wedge-shaped. A gentle beam (goal) conducts pulses from the proproporeceptors of the lower extremities and the lower half of the body and lies medially in the rear cant. The wedge-shaped beam (burgunda) is adjacent to it outside and carries pulses from the upper half of the body and from the upper limbs. The second neuron of this path lies in the same nuclei of the oblong brain. Their processes form the cross in the oblong brain and are connected in a bundle called medial sensitive loop. It comes to the lateral kernel of Talamus (3rd neuron). The processes of third neurons through the inner capsule are sent to the sensitive and partially motor zone of the crust.

Motor tracks are represented by two groups.

1. Pyramid (corticospinal and cortico-nuclear, or corticobulberry) pathways conductive pulses from the bark to the motor cells of the spinal and oblong brain, which are arbitrary movements.

2. Extrapyramidal, reflex motorways included in the extrapyramidal system.

The pyramid, or the corticospinal path begins from large pyramid cells (Betz) of the top 2/3 cortex of precent-centered winding and near-central slices, passes through the inner capsule base of the brain legs, the base of the bridge, the pyramids of the oblong brain. On the border with the spinal cord, it is divided into lateral and front pyramid beams. The side (large) forms the crossroads and descends in the side rope of the spinal cord, ending on the front horns. The front will not crosses and goes in the front rope. By forming a standing cross, its fibers also end on the front horns. Cell processes Anterior horn form the front root, the motor portion of the spinal nerve and end in the muscle of the motor end.

The cortico-nuclear path begins in the lower third of the precentrated winding, goes through the knee (bending) of the inner capsule and ends on the cells of the motor curtain nerve nuclei of the opposite side. Motor nuclei cell processes form a motor portion of the corresponding nerve.

The reflex motor tracks (extrapyramidal) includes red-core-cerebrospinal (Rubroscpinal) path - from the cells of the red core of the mid-brain, the textospinal path - from the kernels of the Mid-Brain roof plate (quadruple), associated with auditory and visual perceptions, and vestiblospinal - from vestibular nuclei From the diamond pits associated with maintaining the equilibrium of the body.

Section "Physiology" of the portal http://medicinform.net

Physiology of spinal cord

The spinal cord is inherent in two functions: reflex and conductive. As the reflex center of the spinal cord is able to carry out complex motor and vegetative reflexes. Afferent - sensitive - paths it is associated with receptors, and efferent - with skeletal muscles and all internal organs.

Long rising and downward spinal cord paths connects double-sided coupling periphery with a brain. The afferent impulses according to the conducting pathways of the spinal cord are carried out in the brain, carrying information about changes in the outer and internal environment of the body. According to the downward paths, the pulses from the brain are transmitted to the effector neurons of the spinal cord and cause or regulate their activities.

Reflex function.Nervous spinal centers are segmental, or workers, centers. Their neurons are directly related to receptors and working bodies. In addition to the dorsal, brain, such centers are available in the oblong and middle brain. Adventure centers, such as intermediate brain, large hemispheres, direct communication with peripherals do not have. They manage it through segmental centers. Motor neurons of the spinal cord innervate all the muscles of the body, limbs, neck, as well as respiratory muscles - the diaphragm and intercostal muscles.

In addition to engine centers of skeletal muscles, there are a number of sympathetic and parasympathetic vegetative centers in the spinal cord. In the lateral horns of the thoracic and upper segments of the lumbar spinal cord, spinal centers of the sympathetic nervous system, innervating heart, vessels, sweat glands, digestive tract, skeletal muscles, i.e. All organs and tissues of the body. It is here that neurons are directly related to peripheral sympathetic gangs.

In the upper breast segment, there is a sympathetic center of the pupil expansion, in five upper breast segments - sympathetic heart centers. In the sacratral departments of the spinal cord, parasympathetic centers are laid, innervating small pelvis organs (reflex centers of urination, defecation, erection, ejaculation).

The spinal cord has a segmental structure. The segment is called such a segment, which gives rise to two pairs of roots. If the frog cut the rear roots on one side, and on the other front, then, the paws on the side, where the rear roots are cut, deprived of sensitivity, and on the opposite side, where the front roots are cut, will be paralyzed. Consequently, the rear spinal cord roots are sensitive, and the front is motor.

In experiments with the cut of individual roots, it was found that each spinal cord segment innervates three transverse segments, or meta-worm, the body: its own, one above and one below. Consequently, each body metaker receives sensitive fibers from three roots and, in order to deprive the sensitivity of the body of the body, it is necessary to cut three roots (reliability factor). Skeletal muscles also receive motor innervation from three neighboring spinal cord segments.

Each spinal reflex has its recipe field and its localization (location), its own level. For example, the center of the knee reflex is in the II - IV lumbar segment; Achilles - in V Lumbar and I - II of the sacral segments; The soles in I - II sacrats, the center of abdominal muscles - in VIII - XII breast segments. The most important vital center of the spinal cord is a diaphragm motor center located in III - IV cervical segments. Damage leads to death due to stopping breathing.

To study the reflex function of the spinal cord, a spinal animal is prepared - a frog, a cat or a dog, making the transverse cut of the spinal cord below the oblong. The spinal animal in response to irritation carries out a defensive reaction - flexion or extension of limbs, checitative reflex - rhythmic flexion of the limbs, proprioceptive reflexes. If the spinal dog is raised behind the front of the body and slightly press it on the sole of the rear leg, then there is a walking reflex - rhythmic, alternate bending and extension of the paw.

Explore spinal cord function.The spinal cord performs the conductive function by ascending and downward paths passing in the white substance of the spinal cord. These paths associate separate segments of the spinal cord with each other, as well as with the brain.

Spinal shock.The reverse or injury of the spinal cord causes a phenomenon that received the name - spinal shock (shock translated from English means hit). The spinal shock is expressed in a sharp drop of excitability and oppression of all the reflex centers of the spinal cord located below the location. During the spinal shock, irritants, usually causing reflexes, are invalid. The injection of paws does not cause a flexing reflex. At the same time, the activities of the centers located above the breaks are preserved. A monkey, which cut the spinal cord was made in the field of the upper breast segments, after the anesthesia passes, the banana takes the front paws, cleans it, brings to his mouth and eats. After cuts, not only skeletal and motor reflexes, but also vegetative are disappeared. Blood pressure is reduced, there are no vascular reflexes, acts of defecation and micake (urination).

The duration of the shock is different in animals standing on different steps of the evolutionary staircase. The frog shock lasts 3 - 5 minutes, the dog - 7 - 10 days, at the monkey - more than 1 month, in person - 4 - 5 months. A shock in a person is often observed as a consequence of household or military injuries. When shock passes, reflexes are restored.

The cause of the spinal shock is to shut down the over-based brain departments that have an activating effect on the spinal cord, in which a large role belongs to the reticular formation of the brain stem.

Physiology of the oblong brain

The oblong brain, as well as the dorsal, performs two functions - reflex and conductive. Eight pairs of cranial nerves are out of the oblong brain and the bridge (from V to XII) and it, as well as the spinal cord, has a direct sensitive and motor communication with the periphery. According to sensitive fibers, it receives impulses - information from the head of the head of the head, mucous membranes of the eyes, nose, mouth (including taste receptors), from the hearing body, the vestibular apparatus (equilibrium body), from the larynx receptors, trachea, lungs, and also from interior cardiac interior - seeking system and digestive system. Through the oblong brain, many simple and most complex reflexes are carried out, covering non-individual body meta chambers, but organic system systems, such as system of digestion, respiration, blood circulation. The reflex activity of the oblong brain can be observed on a bulbar cat, that is, the cat, which produced the reverse of the brain barrel above the oblong. The reflex activity of such a cat is complex and diverse.

The following reflexes are carried out through the oblong brain:

Protective reflexes: cough, chihannie, blinking, tear, vomiting.

Food Reflexes: sucking, swallowing, juice (secretion) of the digestive glands.

Cardiovascular Reflexesregulating the activity of the heart and blood vessels.

In the oblong brain there is an automatically operating respiratory center that provides ventilation of the lungs. In the oblong brain there are vestibular nuclei. From the vestibular cores of the oblong brain begins the descending vestiblospinal tract, participating in the implementation of installation reflexes of the posture, namely in the redistribution of muscle tone. The bulbar cat is not to stand nor walk can, but the oblong brain and the cervical segments of the dorsal provide those complex reflexes that are standing and walking elements. All reflexes associated with the standing function are called installation reflexes. Thanks to them, the animal, contrary to the forces of earthly attraction, keeps the pose of their body, as a rule, the tremors up.

The special meaning of this department of the central nervous system is determined by the fact that in the oblong brain there are vital centers - respiratory, cardiovascular, therefore not only removal, and even damage to the oblong brain ends with death. In addition to the reflex, the oblong brain performs the conductive function. Through the oblong brain, conducting conducting paths connecting bilateral bonds of the bore, intermediate, medium brain, cerebellum and spinal cord.

Mozyology physiology

The cerebellum does not have a direct connection with the receptors of the body. Numerous ways it is associated with all departments of the central nervous system. The afferent (sensitive) conducting pathways, carrying pulses from the proprigororeceptors of muscles, tendons, ligaments, vestibular cores of the oblong brain, subcortical nuclei and bark of large hemispheres are directed. In turn, the cerebellum sends impulses to all departments of the central nervous system.

The cerebellum functions are examined by irritation, partial or complete removal and study of bioelectric phenomena.

The consequences of the removal of the cerebellum and the fallout of his function Italian physiologist Luciani described the famous triada A - Astonia, Atony and Asthenium. Subsequent researchers have added another symptom - ataxia. The cummaged dog stands on widespread paws, performing continuous swing movements ( astasia). It has a proper distribution of the tone of muscles of flexors and extensors ( atony). Movements are poorly coordinated by sweeps, disproportionate, cutting. When walking the paws are thrown over the middle line ( ataxia) What does not happen in normal animals. Ataxia is explained by the fact that the control of movements is disturbed. Analysis of signals from muscle and tendons and tendons are also falling. The dog can not get a muzzle in a bowl with food. Head slope down or aside causes a strong opposite movement.

The movements are very tired, the animal, passing a few steps, falls and rests. This symptom is called asthenia.

Over time, motor disorders at the cumped dog are smoothed. She eats independently, her gait is almost normal. Only biased observation reveals some disorders (compensation phase).

As shown by E.A. Asratyan, compensation of functions occurs due to the cortex of the brain. If such a dog has a bark to remove, then all violations are revealed again and are never compensated. The cerebellum participates in. Regulation of movements, making them smooth, accurate, commensurate.

As shown studies L.A. Orbelli, in beflap dogs, vegetative functions are disturbed. Blood constants, vascular tone, the operation of the digestive tract and other vegetative functions becomes very unstable, easily shifted under the influence of certain reasons (reception of food, muscular work, temperature change, etc.).

When removing half of the cerebellum, the violation of motor functions occurs on the side of the operation. This is explained by the fact that cerebellum pathways either do not intersect at all or crossed out 2 times.

Physiology of mid-brain

Figure: transverse (vertical) incision of the middle brain at the level of the upper hills.

The middle brain plays an important role in the regulation of muscle tone and in the implementation of installation and rectifier reflexes, thanks to which standing and walking.

The role of the middle brain in the regulation of the muscular tone is best observed on the cat, which has a cross-cut between the oblong and middle brain. Such a cat sharply increases the tone, muscles, especially exaggerers. The head throws back, the paws are sharply straightened. The muscles are so strongly reduced that an attempt to bend the limb ends fails - she is straightened now. An animal put on elongated, like sticks, paws, can stand. This condition is called decependence rigidity.

If the incision is above the medium brain, then decertainment rigidity does not occur. After about 2 hours, such a cat makes the effort to rise. At first she raises his head, then the torso, then rises on the paws and can start walking. Consequently, the nervous regulation of muscle tone and standing and walking functions are in the middle brain.

The phenomena of decependence rigidity explain that the red kernels and the reticular formation are separated from the oblong and spinal cord. Red nuclei do not have a direct connection with receptors and effectors, but they are associated with all departments of the central nervous system. Nervous fibers come to them from cerebellum, basal nuclei, cortex of a large brain. From the red nuclei, a descending oblossing path begins, according to which pulses are transferred to the motor neurons of the spinal cord. It is called an extrapyramidal tract. The sensitive cores of the middle brain perform a number of essential reflex features. The kernels located in the upper hills are primary visual centers. They receive impulses from the retina of the eye and participate in an indicative reflex, that is, turning the head to the light. In this case, there is a change in the width of the pupil and curvature of the lens (accommodation), which contributes to a clear vision of the subject.

The cores of the lower holloch are primary auditory centers. They are involved in the approximate reflex to sound - turn head towards sound. Sudden sound and light irritation cause a complicated response of the alarming, mobilizing the animal on a quick response.

Physiology of intermediate brain

The main formations of the intermediate brain are Talamus (visual borgon) and hypothalamus (subbojor region).

Talamus - Sensitive core of the feeder. It is called a "sensitivity collector", as afferent (sensitive) paths from all receptors are converged, excluding the olfactory. Here is the third neuron of afferent paths, the processes of which are ending in sensitive cortex zones.

The main function of Talamus is integration (combining) of all types of sensitivity. To analyze the external environment, not enough signals from individual receptors. Here is a comparison of information obtained on various communication channels, and evaluating its biological significance. In the audience, there are 40 pairs of cores that are divided into specific (on the neurons of these cores, ascending afferent paths are completed), nonspecific (reticular formation nuclei) and associative. Through the associative cores, Talamus is associated with all the logged nuclei of the subcortex - a striped body, a pale ball, a hypothalamus and the cores of the middle and oblong brain.

The study of the functions of the visual buff is carried out by incoming, irritation and destruction.

A cat, which is made above the intermediate brain, is sharply different from the cat, in which the highest department of the central nervous system is the middle brain. It not only rises and walks, i.e. it performs complex coordinated movements, but still exhibits all signs of emotional reactions. Easy touch causes an evil reaction. The cat hits the tail, scalits the teeth, growls, bites, produces claws. A person has a visual borger plays a significant role in emotional behavior, characterized by peculiar facial expressions, gestures and shifts of the functions of the internal organs. With emotional reactions, pressure rises, pulse, breathing, pupils are expanding. Mimic human reaction is congenital. If you rinse the nose of the fetus 5 - 6 months, you can see a typical displeasure grimace (PK Anokhin). When irritating the visual wall in animals, motor and pain reactions occur - squeal, grumbling. The effect can be explained by the fact that impulses from visual bugs easily go to the detailed nuclei associated with them.

In the clinic, symptoms of the defeat of visual bumps are strong headache, sleep disorders, sensitivity disorders, both in the direction of increasing and lowering, disruption of movements, their accuracy, proportionality, the occurrence of violent involuntary movements.

Hypothalamus He is the highest subcortex center of the vegetative nervous system. In this area there are centers governing all the vegetative functions that ensure the constancy of the inner environment of the body, as well as regulating fat, protein, carbohydrate and water-salt exchange.

In the activities of the vegetative nervous system, the hypotalamus plays the same important role as the red cores of the middle brain play in the regulation of the skeletal-motor functions of the somatic nervous system.

The earliest studies of the functions of the hypothalamus belong to TOloda Bernard. It discovered that the injection of the rabbit in the intermediate brain causes an increase in body temperature by almost 3 ° C. This classic experience, which opened the localization of the thermoregulation center in the hypothalamus, received the name of the heat injection. After the destruction of the hypothalamus, the animal becomes a caothelotermic, i.e. it loses the ability to keep the constancy of the body temperature. In the cold room, the body temperature decreases, and in hot rises.

Later it was found that almost all organs innervated by the vegetative nervous system can be activated by irritation of the subbojor region. In other words, all the effects that can be obtained in the irritation of sympathetic and parasympathetic nerves are obtained by irritating the hypothalamus.

Currently, the method of impact of electrodes is widely used for irritation of various brain structures. With the help of a special, so-called stereotactic technique, the electrodes into any specified area of \u200b\u200bthe brain are introduced through the trepanitative hole in the skull. Electrodes are isolated all over, only their tip is free. Including electrodes in the chain, you can narrowly irritate those or other zones.

When irritating the front sections of the hypothalamus, parasympathetic effects occur - the increase in the intestinal movements, separation of digestive juices, the slowdown in the abbreviations of the heart, etc. In case of irritation of the rear sections, sympathetic effects are observed - the increase in the heartbeat, the narrowing of the vessels, the increase in body temperature, etc. Consequently, in the front sections of the subbozhny region Parasympathetic centers are located, and in the rear - sympathetic.

Since irritation with the help of implanted electrodes is performed on the whole animal, without anesthesia, it seems to be able to judge the behavior of the animal. In the experiments of Andersen on a goat with implanted electrodes, the center was found, the annoyance of which causes the unattricible thirst, - the center of thirst. With his irritation, the goat could drink up to 10 liters of water. An irritation of other sites could be made a fusion animal (star of hunger).

Experiments of the Spanish Scientist Delgado on the bull with an electrode, implanted to the center of fear, were widely fame: when the enemy was a furious bull rushed onto the toleador, included irritation, and the bull retreated with clearly pronounced signs of fear.

The American researcher D. OLDZ offered to modify the method - to provide the opportunity to the animal himself to climb that the animal will avoid unpleasant irritation and, on the contrary, to strive to repeat pleasant. Experiments have shown that there are structures whose irritation causes an unrestrained desire for repetition. Rats brought themselves to exhaustion by pressing the lever up to 14,000 times! In addition, the structures were found, the irritation of which, apparently, causes an extremely unpleasant feeling, as the rat avoids a second time to press the lever and runs away from it. The first center is obviously the center of pleasure, the second - the center of displeasure.

Extremely important for understanding the functions of the hypothalamus was the discovery of the brain of receptors, capturing changes in blood temperature (thermistors), osmotic pressure (osimorceptor) and blood composition (gluchoreceptors).

With receptors facing blood, reflexes arise aimed at maintaining the constancy of the inner environment of the body - homeostasis. "Hungry Blood", irritating gluchoretoles, excites the food center: There are food reactions aimed at searching and eating food.

One of the frequent manifestations of the disease of the hypothalamus in the clinic is a violation of water-salt metabolism, manifested in the allocation of a large amount of urine with low density. The disease is called unsauchery diabetes.

Subbojor region is closely related to the activities of the pituitary. In large neurons of the supervisory and arrogant nuclei of the hypothalamus, hormones are formed - vasopressin and oxytocin. According to axon, hormones flow to the pituitary gland, where they accumulate, and then enter blood.

Other relationship between the hypothalamus and the front fraction of the pituitary gland. The vessels surrounding the cores of the hypothalamus are combined into the veins system, which descend to the front share of the pituitary gland and are divided into capillaries. With blood to the pituitary gland, substances are income - releases, or liberating factors that stimulate the formation of hormones in the front of it.

Reticular formation.In the brain barrel - oblong, middle and intermediate brain, between its specific nuclei there are clusters of neurons with numerous highly branching processes that generate a thick network. This neuron system has been the name of a net education, or a reticular formation. Special studies have shown that all the so-called specific ways conducting certain types of sensitivity from receptors to the sensitive zones of the cerebral cortex are given in the branch brain barrel, ending on the reticular formation cells. Pulse streams with peripherals from extero, intermediate and proprigororeceptors. Support constant tonic excitation of reticular formation structures.

Non-specific paths begin on the neurons of the reticular formation. They rise up to the cerebral cortex and subcortex nuclei and descend down to the neurons of the spinal cord.

What is the functional significance of this peculiar system that does not have its own territory located between the specific somatic and vegetative core cores?

The method of irritation of individual structures of the reticular formation was able to disclose its function as a regulator of the functional state of the spinal and brain, as well as the most important regulator of the muscle tone. The role of the reticular formation in the activities of the central nervous system is compared with the role of the regulator on the TV. Not giving images, it can change the volume of sound and illumination.

The irritation of the reticular formation, without causing the motor effect, changes the existing activity, braking it or enhanced. If the cat has short, rhythmic irritations of a sensitive nerve to cause a protective reflex - bending the back leg, and then on this background to join the irritation of the reticular formation, then, depending on the irritation zone, the effect will be different: spinal reflexes are either sharply intensified, or weaken and disappear, t. e. Protect. Braking occurs when irritating the rear sections of the brain trunk, and the strengthening of reflexes - when irritating the front departments. The corresponding zones of the reticular formation were called the braking and activating zones.

On the bark of the brain, the reticular formation has an activating impact, maintaining the state of wakefulness and concentrating attention. If the sleeping cat with implanted in the intermediate brain electrodes include irritation of the reticular formation, then the cat wakes up, opens his eyes. The electroencephalogram shows that slow waves are disappearing, characteristic of sleep, and quick waves appear, characteristic of the wakefulness. The reticular formation has an upward, generalized (covering the entire Cora) activating influence on the bark of the brain. By expression I.P. Pavlova, "Cooking charges a bark." In turn, the bark of large hemispheres regulates the activity of the net education.

Physiology ch-ka:Compendium.. Tutorial for higher educational institutions / Ed. Acad Ramne B.I.kachenko and prof. V.F. Pyatina, St. Petersburg. - 1996, 424 p.

central nervous system

central nervous system(CNS) - a set of nervous formations of the dorsal and brain, providing perception, processing, transmission, storage and reproduction of information in order to adequately interacting the body with environmental changes, the organization of the optimal functioning of organs, systems and the body as a whole.

Neuron and Neuroglia

Neuron -the structural and functional unit of the nervous system is able to receive, process, encode, store and transmit information, respond to irritation, to establish contacts with other neurons and organs of organs. Functionally neuron consists of perceivedparts (dendrites, soma neuron membrane), integrative(Soma with axonal holloch) and transfer(Aksonal Hollyk with Axon).

Dendriti,usually several, their membrane is sensitive to mediators and has specialized contacts to perceive signals - spines. The harder the function of neurons, the more spines on their dendrites. Most of all the spines on the pyramidal neurons of the motor cortex. Spizes disappear if you do not receive information.

Soma.neuron performs informationaland trophicfunctions (growth of dendrites and axon). Soma contains the kernel and inclusion that ensure the functioning of the neuron.

Functionally neurons are divided into three groups: afferent -receive and transfer information to the overlying department of the CNS, intermediate -provide connections between the neurons of one structure and efferent -transfer information to the structures of the central nervous system or to the tissues of the body. According to the type of mediator, neurons are divided by choline, peptide, norepinephrine-. Dopamine-, serotonergicet al. Neurons are separated by mono-and polyessential,responding to signals of one (light or sound), two (light and sound) and more modalities. For the manifestation of neurons activity happens: phonovoactive(generate pulses continuously with different frequency) and silent(React only to the presentation of irritation).

Functions Neuroglin(astroglyocytes, oligodendroglyocytes, microglyocy-you). Glia -small cells of various forms in the amount of 140 billion, fill the spaces between neurons and capillaries, accounted for 10% of the volume of the brain. Astroglyocytes -manproof cells with a size of 7 to 25 microns. Most of the processes ends on the walls of the vessels. Astroglyocytes are supporting neurons, provide reparative processes of nerve trunks, isolate the nerve fiber, participate in the metabolism of neurons. Oligodendroglyocytes -cells that have a small number of processes. Oligodendroglyocytes are more in subcortical structures, in the brain barrel, less - in the cortex. They are involved in the myelinization of axons and in the metabolism of neurons. Microhyloocytes -the smallest cells of the glill are capable of phagocytosis.

Glial cells are capable of rhythmically change their size, while the processes swell without a change in length. "Pulsation" of oligodendroglyocytes reduces serotonin, and enhances - norepinephrine. The function of "pulsation" of glial cells is the pushing of the neurons axoplasm and the creation of the fluid current in the intercellular space.

Information function of the nervous system.Separate neuron perceives, processes and sends signals to the executive system, performing a function coding.

In the nervous system, information is encoded by non-pulse and pulsed (discharge of the nervous cell) codes. Spatio-temporal coding and coding with labeled lines are carried out when the activity of the nervous system is changed. Nonipulcifiedinformation coding is expressed as a change in receptor, synaptic or membrane potentials. Pulsethe coding in the nervous system dominates over an unlimited and is carried out: frequency and interval coding, latent period, the duration of the reaction, the likelihood of the appearance of the pulse, the variability of the pulsation frequency. Frequency codingit is carried out by the amount of pulses per unit of time. For example, the irritation of the motionerone with one frequency causes a reduction in one group of fibers, and the other frequency - excites another group of muscle fibers. Interval codingit is carried out by various temporal intervals between pulses at their permanent average frequency. For example, the muscles are reduced many times stronger if the nerve is irritated by an unregulated pulse flow. Power of irritationit is encoded by the time of the latent period of the appearance of the response of the nervous cell, as well as the number of pulses and the reaction time of the neuron. All coding methods rarely protrude in its pure form.

Quality of irritationit is encoded by interval, space-time methods and labeled lines. Spatial and spatial-temporal coding is the encoding of information by the formation of a specific spatial and temporary mosaic of excited and inhibited neurons. Coding with labeled linesit assumes that any information that comes from this receptor is estimated in the core as a message of one quality.

Information coding efficiency increases with an increase in the speed of its transfer. Reliability of information transfer in the nervous system is due to duplication of communication channels, elements and systems (Structural redundancy)and "excess" number of impulses in the discharge, as well as an increase in the excitability of the nervous cell (Functional redundancy).

Spinal cord

Morphofunction spinal cordorganized in form segmentsdivision to which is determined by the distribution zones of the cells forming rear afferent(sensitive) and front effectant(Motor) roots (Bella-Majandi law).

The afferent inlets of the spinal cord are formed by the entrances from receptors:

1) proprioceptive sensitivity, muscle receptors, tendons, periosteum, joint shells;

2) skin reception (pain, temperature, tactile, pressure);

3) visceral organs - visceoresepping.

The functions of the neurons of the spinal cord.Functionally neurons of the spinal cord are divided into α- and γ-motoneons, interneurons, neurons of the sympathetic and parasympathetic system.

Motonightonsinnervate muscle fibers, forming motor unit.In the muscles of precise movements (ooo) one nerve innerves the smallest amount of muscle fibers. Motioneons innervating one muscle form motionron pool.The single pool motioneons have different excitability, so they are involved in activity depending on the intensity of their stimulation. Only with the optimal power of irritation of motioneons of the pool, all the fibers of the muscles innervated by this pool are involved in the reduction. α-motiononeons have direct connections with extrusive muscle fibers, have a low pulsation frequency (10-20 / s). γ-motoneurons innervate only intraphus muscle muscle spindle fibers. Neurons have a high pulsation frequency (up to 200 / s) and receive information - about the state of muscular spindle through intermediate neurons.

Interneurone(Intermediate neurons) generate up to 1000 pulses per second. Interneuronov function:organization of ties between the structures of the spinal cord; braking neuron activity while preserving the direction of excitation path; Reciprocal braking of motorcycles innervating antagonist muscles.

Neurons sympatheticsystems are located in the side horns of the thoracic spinal cord, their background activity is 3 - 5 pulses in sec. The defiances of neurons correlate with blood pressure oscillations.

Neurons parasympatheticsystems are also phoactive, localized in the sacral spinal cord department. Neurons are activated when irritating the pelvic nerves, sensitive nerves of the limbs. The frequency of their discharges increases the reduction of the muscles of the bladder walls.

Current spinal cordformed axons of neurons of spinal ganglia and gray spinal cord substance. Functionally conducting ways are divided into proprodospinal, spinacerebral and cerebrospinal. Propropinal pathsstart from neurons of the intermediate zone of some segments and go to the intermediate zone or on the front horns of other segments of the front horns. Function: Coordination of postures, muscle tone, movements of different body metameters. Spinocerebralpaths (proprioceptive, spinatelamic, spinosochal, spinigorological) combine the spinal cord segments with the head structures. Proprioceptivepath: Receptors for the deep sensitivity of muscle tendons, periosteum and joints of the joints - spinal ganglia - rear cores, cores of goal and bourdaha (first switching) - contralateral thalamus kernels (second switching) - somatosensory cortex neurons. In the course of the fibers of conductive paths, the collaterals are given in each spinal cord segment, which creates the ability to correct the poses of the entire body. Spinolamic path:pain, temperature and tactile leather receptors - spinal ganglia, rear horns of the spinal cord (first switching) - contralateral side rope and partially front rope - Talamus (second switching) - sensory bark. Somatovisceral afferets also go along the spinoreticular path. Screenshots:golgi tendon receptors, proprigororeceptors, pressure receptors, touch - non-cerebral beam of Govers and twice crossed flexing bundle - cerebellone hemispheres.

Cerebrospinal Ways: Corkospinaly -from pyramid neurons of pyramid and extrapyramidal cortex (regulation of arbitrary movements), rubronspinal, Vestibloscino, reticulospinaly -regulate the tone of muscles. The final point of all paths are the front horns of the spinal cord.

Reflexes of the spinal cord.Reflex reactionsthe spinal cord is carried out by segmental reflex arcs, their character depends on the area and force of irritation, the area of \u200b\u200ban irritable reflexogenic zone, the velocity of carrying out the afferent and efferent fibers, the effects of the brain. From the recipe field of the reflex information about the irritant on sensitive and central neuron fibers of the spinal ganglia can go straight to the front horns of the front horns whose axone innerves muscle. This generates a monosynaptic reflex arc, which is one synaps between the afferent neuron and the motoneron. Monosianaptic reflexesthere are only when irritating the receptors of annifarpiral endings of muscular spindles. Spinal reflexes implemented with the participation of the rear horn or the spinal cord intermediate region are called polischapttesky.

Types of polysinactic reflexes: motatical(reflex reduction of the muscles on its rapid stretching, for example, a blow hammer over tendon); from skin receptors; Vesteromotor(Motor reactions of the muscles of the chest and the abdominal wall, the muscle spins of the back in the stimulation of the afferent nerves of the internal organs); vegetative(the reactions of internal organs, the vascular system for irritation of visceral, muscle and skin receptors). Vegetative reflexes have their own characteristics - a large latent period and two phases of the reaction. The early phase (latent period of 7 - 9 ms) is implemented by a limited number of segments, and the late (latent period to 21 c) - involves all the segments of the spinal cord and the vegetative centers of the brain in the reaction.

The complex activity of the spinal cord is the organization of arbitrary movements, which is based on a U-afferent reflex system. It includes: the pyramid bark, an extrapyramidal system, α- and γ-motor neurons of the spinal cord, extra- and intrafusal muscular spindle fibers.

The complete intersection of the spinal cord in the experiment or in a person during injury causes spinal shock(shock strike). All centers below the cuts are ceased to carry out reflexes. The spoon shock in different animals lasts different times. The monkeys of the reflexes begin to appear in a few days, in a person in a few weeks, and even months.

The reason for the shock is the violation of the regulation of reflexes from the head of the brain. Repeated reverse of the spinal cord below the place of the first cut does not cause spinal shock.

Brain stem

The brain trunk includes the oblong brain, Barolic Bridge, the middle brain, the intermediate brain and the cerebellum. Brain stem functions: reflex, associative, conductor.The paths of the brain stem connect among themselves the various structures of the CNS and when organizing behaviors ensure their interaction among themselves (Associative function).

Functions of the oblong brain- Regulation of vegetative and somatic taste, auditory, vestibular reflexes due to specific nervous nuclei and reticular formation.

Functions of a wandering nerve nuclei:receive information from the heart, parts of the vessels, the digestive tract, lungs and regulate their motor or secretory reaction; reinforce the reduction of smooth muscles, stomach, intestines, gallbladder and relax the sphincters of these organs; slow down the work of the heart, reduce the lumen of the bronchi; Stimulate the secretion of bronchial, gastric, intestinal glands, pancreas, secretory liver cells.

Center salivationenhances the overall (parasympathetic part) and protein secretion (sympathetic) of the salivary glands.

In the structure of the reticular formation of the oblong brain, vessels and respiratory centers are located. Respiratory Center -symmetric education; The voltage activity of its cells correlates with the rhythm of inhalation and exhalation. [...]

Vasomotor Centerreceives afferentation from vessel receptors, through other brain structures from bronchiole, hearts, abdominal organs, somatic receptors. The efferent paths of reflexes go along the reticulous removal path to the side horns of the spinal cord (sympathetic centers). Blood pressure reactions are dependent on the type of sympathetic neurons of the spinal cord and from their frequency of discharges. High-frequency impulsation increases, and low-frequency - reduces blood pressure. The vasomotor center also affects the respiratory rhythm, the tone of the bronchi, the muscles of the intestine, the bladder, the ciliary muscles. This is due to the fact that the reticular formation of the oblong brain binds it to the hypothalamus and other nervous centers.

Protective reflexes:vomiting, sneezing, cough, tear, closure of the eyelids. Irritation of the receptors of the mucous membrane, the oral cavity, larynx, nasopharynx through the sensitive branches of the triple, languagehiller and the wandering nerves excites the motor centers of the trigeminal, wandering, tongue, facial, additional or sub-speaking nerves, thus, a particular protective reflex is implemented. An oblong brain is involved in the organization food Reflexes:sucking, chewing, swallowing.

Reflexes of maintaining poseformed with the participation of receptors of the thread of the snail and semicircular channels, neurons of the lateral and medial vestibular cores of the oblong brain. Neurons of the medial and lateral kernels in the vestiblospinal journey are associated with motor mechanons of the corresponding spinal cord segments. As a result of the activation of these structures, the muscle tone changes, which creates a certain path of the body. Distinguish static reflexes poses(regulate the tone of skeletal muscles in order to hold a certain position of the body) and stocietic reflexes(Muscle tone redistribute for organizing poses, at the moment of straight or rotational motion).

The cores of the oblong brain carry out a primary analysis of the strength and quality of various irritations (the reception of the skin sensitivity of the face-andyadro-nerve; the reception of the taste is the kernel of the tongue nerve; the reception of the auditory irritation is the kernel of the auditory nerve; the reception of vestibular irritation is the top vestibular kernel) and transmit the processed information in the subcount Structures to determine the biological significance of the stimulus.

The functions of the bridge and mid-brain.Bridgecontains ascending and descending paths that bind the front brain with the spinal, cerebellum and other structures of the barrel. The neurons of the bridge form a reticular formation, the kernels of the facial, discharge nerve, the motor part and the average sensory nucleus of a trigeminal nerve are localized. The neurons of the reticular formation of the bridge activate or inhibit the bark of the brain, are associated with a cerebellum, spinal cord (reticulospinal path). In the reticular formation of the bridge there are also two groups of the cores: one - activates the center of breath of the oblong brain, the other is the exhalation center, which leads to the operation of the respiratory cells of the oblong brain in accordance with the changing condition of the body.

Medium brainpresented by quirms and legs of the brain. Red kernel(the upper part of the brain leg) is associated with the brain bark (descending from the crust of the path), subcortical nuclei (basal ganglia), cerebellum, with a spinal cord (obliging path). The violation of the red core bonds with the reticular formation of the oblong brain leads to the decependence rigidity in animals (the strong voltage of the muscle-extensors of the limbs, neck and back), which indicates the braking influence of this core on the neurons of the reticulospinal system. The red core, receiving information from the motor cortex, subcortical nuclei and the cerebellum about the preparing motion and the state of the musculoskeletal system, sends the corrective pulses to the spinal cord motor mechanons over the rubry-block path and, thereby, regulates the muscles tone.

Black substance(Brain's legs) regulates acts of chewing, swallowing, their sequence, ensures accurate movements of the fingers of hand brush, for example when writing. The neurons of this nucleus are synthesized by the Mediator Dopamine, which is supplied by axonal transport to the basal ganglia of the brain.

Raising the Eye Century, eye movement up, down, to the nose and down to the corner of the nose adjusts the core of the ooo nerveand turn turns up and out - core of block nerve.In the middle brain there are neurons,

the regulating lumen of the pupil and the curvature of the lens, the result is an adaptation of the eye for the better vision.

Reticular formationthe mid-brain takes part in the regulation of sleep. The braking of its activity causes sleepy spindle mehers, and stimulation is a reaction of awakening.

IN upper furrah Quadrahmiathere is a primary switching of visual paths from the retina, and in lower Forms -second and third switching from auditory and vestibular organs. Next, the afferentation enters the crankshafts of the intermediate brain. The axons of neurons of the bugs of the bugs are coming to the reticular formation of the brain stem and the spinal cord motnelones (tectospinal path). The main function of the Bugrov Quaggers is the organization of the reaction of the alarming and the so-called "start-reflexes" for sudden, still unrecognized visual or sound signals. In these cases, the middle brain is activated through the hypothalamus, increasing the muscle tone, the student of the reduction of the heart, forms the response of avoidance or defensive reaction. Quarterly organizes approximate visual and auditory reflexes.

Intermediate brain(Talamus, hypothalamus, pituitary gland) integrates sensory, motor and vegetative reactions necessary for the integral activity of the body.

Talamus functions:1) processing and integration of all signals going to the bark of the brain from neurons of the spinal cord, mid-brain, cerebellum, basal ganglia; 2) Regulation of the functional states of the body. In Talamus, about 120 multifunctional nuclei, which on the projection in the Cora are divided into three groups: front -projects the axons of their neurons into the belt bark; medial -in any; lateral -in dark, temporal, occipient. The functions of the Talamus nuclei are determined by its afferent connections. There are signals from visual, auditory, flavor, skin, muscle systems, from the cerebral nerve nuclei of the barrel, cerebellum, a pale bowl, an oblong and spinal cord. Talamus kernels divide on specific, nonspecificand associative.

Specific nuclei(front, ventral, medial, ventral, postlatral, post -med, lateral and medial crankshafts - subcortex centers of view and hearing) contain "relay" neurons that switch paths going to the bark from skin, muscle and other types of sensitivity and direct them in Strictly defined areas of the 3 - 4th layers of the crust (somatotopic localization). The specific cores of Talamus also have a somatotopic organization, therefore, in violation of their function, specific types of sensitivity occurs.

Associative nuclei(Medioderal, Lateral, Dorsal and Talamus Pillow) contain polybitensor neurons that are excited by different irritations and send an integrated signal to the associative bark of the brain.

A axons of neurons of the associative nuclei of Talamus go to the 1st and 2nd layers of associative and partially projection areas of the cortex, along the way, giving collaterals in the 4th and 5th layers of the crust and forming axomatic contacts with pyramidal neurons.

Nonspecific nucleitalamus (median center, paracentral core, central, medial, lateral, sub-permanent, ventral front and paraphaccular complexes, reticular kernel, perivativeri-choroic and central gray mass) consist of neurons whose axons rise to a bark and in contact with all its layers, forming Diffuse connections. There are signals from the reticular formation of the brain, hypothalamus, a limbic system, basal ganglia, specific cores of the Talamus to the nonspecific Talamus nuclei. The excitation of nonspecific nuclei causes generation in the crust of spindle-shaped electrical activity, indicating the development of a sleepy state.

The functions of the hypothalamus.Hypothalamus - complex of polyfunctional intermediate structures having afferent connectionswith olfactory brain, basal ganglia, thalamus, hippocampus, orbital, temporal, dark bore, and efferent connection -with Talamus, reticular formation, vegetative centers of the trunk and spinal cord. Functionally nuclear structures of the hypothalamus are divided into three groups and perform integrating functionvegetative, somatic and endocrine regulation.

Front group of kernelsadjusts the recovery and preservation of the organism reserves by parasympathetic type, produces railing factors (liberins) and inhibitory factors (statins), controls the function of the front lobe of the pituitary thermoregulation by heat transfer(extension of blood vessels, strengthening of breathing and sweating) causes sleep.

Medium group of kernelsreduces the activity of the sympathetic system, perceives changes in blood temperature (central thermistorceptor), electromagnetic composition and osmotic plasma pressure (hypothalamus Osoryceptor), as well as the concentration of blood hormones.

Rear group of kernelscauses sympathetic reactions of the body (the expansion of pupils, increased blood pressure, the increase in the rhythm of heart abbreviations, inhibition of intestinal motility), provides temoregulationway heat Production(increase in metabolic processes, heart rate, muscle tone), forms food Behavior(Food search, salivation, circulatory stimulation and intestinal motor skills), regulates the cycle "Wake-up-sleep."Selective damage of various rear hypothalamus cores can cause sopor,fasting (AphaGHA) or excessive food intake (hyperfagia), etc.

In the hypothalamus there are regulation centers: homeostasis, thermoregulation, hunger and saturation, thirst, sexual behavior, fear, rage, regulation of cycle "Wake-sleep".The specifics of the neurons of the hypothalamus are their sensitivity to the composition of the washing blood, the absence of a hematoreke-phalochic barrier, neurosection of peptides and neurotransmitters.

Pituitarystructurally functionally connected with the hypothalamus. Rearthe pituitary glands (neurohypophysis) accumulates the hormones produced by the hypothalamus, which regulate the water-salt metabolism (vasopressin), the function of the uterus and the mammary glands (oxytocin). Front Sharethe pituitary glands produces: adrenocorticotropic hormone (stimulates adrenal glands); thyrotropic hormone (the regulation of the thyroid gland); Gonadotropic hormone (gender regulation); somatotropic hormone (rising bone system); prolactin (growth regulator and the secretion of the mammary glands). The hypothalamus and the pituitary gland also form neuroregulatory enkephalins and endorphins (morpho-suicide substances) that reduce stress.

The functions of the reticular formation of the brain.The reticular formation of the brain is the network of neurons of the oblong, medium and intermediate brain associated with all the structures of the CNS. The generalized nature of the effects of the reticular formation makes it possible to consider it nonspecific systembrain. Features of her function:

1) compensation and interchangeability of network elements;

2) reliability of the functioning of neural networks;

3) the diffusion of connections between network elements;

4) steady background reactive impulses of neurons;

5) the presence of background solid neurons that quickly react to sudden, unidentified visual and auditory signals;

6) the organization of motor activity with the participation of vestibular and visual signals;

7) the formation of a common diffuse, uncomfortable feeling;

8) adaptation (reduction) of neuron activity in their repeated irritations (nomine neurons);

9) The neurons of the reticular formation of the bridge inhibit the activity of motionerons of the thrifter muscles and excite the motionones of the extensors. Opposite effects cause re-neurons of the oblong brain;

10) the activity of neurons of all departments of the reticular formation facilitates the reactions of motor spinal cord systems;

11) the reticular formation of the oblong brain synchronizes the activity of the cortex of the brain (the development of slow rhythms of EEG or a sleepy state);

12) the reticular formation of the mid-brain desynchronizes the activity of the cortex (the effect of awakening, the development of fast Rhythms of EEG);

13) regulates the activity of respiratory and cardiovascular centers.

Cerebellum functions.Cerebellum - integrative Structurebrain coordinates and regulates arbitraryand involuntary movements, vegetativeand behavioral functions.Features of the cerebulic bark:

1) stereotypical structure and communication;

2) a large number of afferent entrances and the only axon exit - Purkinier cells;

3) Purkinier cells perceive all types of sensory irritation;

4) The cerebellum is associated with the structures of the front brain, the trunk and the spinal cord.

In cerebellum distinguish: archobellyum(an ancient cerebellum), is associated with the vestibular system and regulates the equilibrium; paleocebellum(old cerebellum - worm, pyramid, tongue, paraphloctary department), gets information from muscle proproportors, tendons, periosteum, joint shells; neocebellyum(new cerebellum - cerebel cerebeller cerebellone, sections of the worm), which through the frontal-bridges, adjusts visual and hearing motor reactions.

The afferent communication of the cerebellum:1) leather receptors, muscles, articular shells, periosteum - dorzal and ventral spinosochalts - the lower olives of the oblong brain - further through the climbing fibers on the dendrites of Purkinier cells; 2) the nuclei of the bridge - the system of mossy fibers - grain cells, which are polysinapotically associated with Purkinier cells; 3) The blue stain of the middle brain is adrenergic fibers that distinguish between norepinephrine in the intercellular space of the cerebeller's crust, changing the excitability of its cells.

Efferent paths of the cerebellum:through the upper legs go to the Talamus, Barolic Bridge, the Red core, the core of the brain, the reticular formation of the mid-brain; Through the lower legs of the cerebellum - to the vestibular nuclei of the oblong brain, oliv, the reticular formation of the oblong brain; Through the average legs - bind neocebellum with a frontal bark. Efferterent signals from the cerebellum in the spinal cord regulate the power of muscle contractions, support the normal tone of the muscles alone and with the movement moves arbitrary movements with their goal, contribute to the change of bending and extensive movements, as well as long-term tonic contractions.

Violation of the regulatory functions of the cerebellum causes the following disorders of the movements: asthenium -reduction of muscle reduction strength, fast muscle fatigue; astasia -loss of ability to long-term muscle cuts, which makes standing, sitting; distopia -involuntary increase or decrease in muscle tone; tremor -trembling fingers, heads in peace (enhanced when moving); dommetry -disorder of movements in the form of superfluous (Hypermmetry)or insufficient (hypometry)actions; ataxia -violation of coordination of movements; dysarthria -speech motility disorder. The decrease in the functions of the cerebellum violates, first of all, the order and sequence of movements that were acquired by a person as a result of training.

Through collaterals of the pyramidal path of the motor area of \u200b\u200bthe large brain cortex lateral and the intermediate area of \u200b\u200bthe cerebeller's cortex, receive information about the preparing arbitrary movement. The latral cerebral cortex sends the signals to his gear core, then information on the cerebelchikovo-cortical journey goes to the sensorobic bark. At the same time, the signals through the cerebelchikovo-scrapping path, the red core and then on the ruble path reaches the spinal cord motnelones. In parallel, the same motioneons receive signals on the pyramid path from the neurons of the cerebral cortex. In general, the cerebellum correlates the preparation of movement in the cerebral cortex and prepares the tone of muscles to implement this movement through the spinal cord. Since the cerebellum brakes the mitatatic and labyrinth reflexes through the neurons of the vestibular nucleus, then when the cerebellum is damaged, the vestibular kernels uncontrollably activate the motionons of the front horns of the spinal cord. As a result, the tone of muscle extensor of the limbs increases. Simultaneously, propriceceptive reflexes of the spinal cord are released, as the inhibitory effect is removed on its motioneons from the reticular formation of the oblong brain.

The cerebellum activates the pyramidal neurons of the cortex, which inhibit the activity of the spinal cord motioneons. The larger the cerebellum activates the pyramidal neurons of the cortex, the more pronounced the braking of the spinal cord motionoons. When cerebellum damage, this braking disappears, since the activation of the pyramid cells stops.

Thus, with damage to the cerebellum, neurons of vestibular nuclei and the reticular formation of the oblong brain are activated, which stimulate the spinal cord motioniron. At the same time, the braking effect of the pyramid neurons on the same spinal cord motories is reduced. As a result, receiving exciting signals from the oblong brain and not receiving braking from the bark, the spinal cord motories are activated and cause muscle hypertonus.

The cerebellum through the oppressive and stimulating effects on cardiovascular, respiratory, digestive and other organism systems stabilizes and optimizes the functions of these systems. The nature of the change depends on the background on which they are called: when irritating the cerebellum, high blood pressure decreases, and the initial low increases. In addition, when the cerebellum is excited, the body's systems are activated by the type of sympathetic reaction, and during damage it is prevailing the opposite effects.

Thus, the cerebellum takes part in various activities of the body (motor, somatic, vegetative, sensory, integrative), optimizes the relationship between various sections of the CNS.

The man's spinal cord is the most important organ of the central nervous system, communicating all organs from the central nervous system and conducting reflexes.

It is covered with three shells: solid, cute and soft.

Between the web and soft (vascular) shell and in the central channel there is a spinal fluid (liquor)

In epidural space (the gap between the solid cerebral shell and the surface of the spine) - vessels and adipose tissue

The structure and functions of the spinal cord of a person

What is the spinal cord on the external structure?

This is a long cord in the spinal Channel, in the form of a cylindrical shape, about 45 mm long, about 1 cm wide, a flatter front and rear than on the sides. It has a conditional upper and lower boundaries.

The top begins between the line of a large occipital hole and the first cervical vertebra: in this place the spinal cord is connected to the head through the intermediate oblong.

Lower - at the level of 1 -2 lumbar vertebrae, after which the cord takes a conic appearance and then "degenerates" into a thin cerebrospinal thread (terminal) with a diameter of about 1 mm, which stretches to the second vertebra of the cockerel department. The terminal thread consists of two parts - internal and outdoor:

• internal - approximately 15 cm long, consists of nervous tissue, is intertwined with lumbar and sacrilant nerves and is located in a solid brain sheath bag
• outdoor - about 8 cm, begins below the 2nd vertebral of the sacrilate department and stretches in the form of a compound of solid, web and soft shells up to the 2nd cleaned vertebra and sprouts with periosteum

The outer, hanging to the square itself the terminal thread with the intertwing nerve fibers is very reminded by the type of horse tail. Therefore, pain and phenomena arising from pinching nerves below the 2nd sacrilate vertebra are often called horse-tail syndrome.

The spinal cord has thickening in the cervical and lumbosacral departments. This finds its explanation in the presence of a large number of nerves in these places going to the top, as well as to the lower limbs:

1. The cervical thickening is distributed on the length of the 3rd - 4th cervical vertebrae to the 2nd breast, reaching a maximum in the 5th - 6th
2. Lumbar-sacral - from the level of the 9th - 10th breast vertebrae to the 1st lumbar with a maximum of 12th breast

Gray and white spinal cord substance

If you consider the structure of the spinal cord in the cross-section, then in the center it can be seen a gray area in the form of a butterfly opened its wings.

This is a gray spinal cord substance. It is surrounded by a white substance.

The cellular structure of the gray and white substance differs among themselves, as well as their functions.

The gray substance of the spinal cord consists of motor and inserted neurons:

• motor neurons transmit motor reflexes
• inserts - provide communication between the neurons themselves

White substance consists of so-called axons - nerve processes, of which fibers are descending and ascending conductive pathways.

The wings "Butterflies" are narrower forming the front horn of the gray substance, wider - rear. In the front horns there are motor neurons, in the rear - insert.

Between the symmetric lateral parts there is a transverse jumper from the brain tissue, in the center of which the channel passes, communicating the upper part with the ventricle of the brain and filled with the spinal fluid.

In some departments or even throughout adults in adults, the central canal can overeat.

Relative to this channel, on the left and right of it, the gray substance of the spinal cord looks like a pillars of a symmetrical shape, interconnected by the front and rear spikes:

• front and rear poles correspond to the front and rear horns on the cross section
• side protrusions form a side pillar

The side protrusions are not for the whole length, but only between the 8th cervical and 2nd lumbar segments. Therefore, the transverse cut in segments, where side protrusions are lacking, has an oval or round shape.

The connection of symmetric pillars in the front and rear parts forms two furrows on the surface of the brain: anterior, deeper, and rear. The front gap ends with a partition adjacent to the rear border of the gray substance.

Spinal nerves and segments

On the left and right of these central grooves are located, respectively, oppositely and rear agents, through which the front and rear threads (axons) are overlooking the nerve roots.

The front root in its structure is the motor neurons of the front horns. The rear responsible for sensitivity consists of inserting rear horn neurons.

Immediately at the outlet of the brain segment and the front and rear spores are combined into one nerve or nerve knot (ganglia).

Since all in each segment there are two front and two rear roots, in the amount they form two cerebral nerves (one on each side). Now it is not difficult to calculate how much nerves has a spinal cord of a person.

To do this, consider its segmental structure. Total there are 31 segments:

• 8 - in the cervical department
• 12 - in breast
• 5 - lumbar
• 5 - in the sacrats
• 1 - in the copier

So the spinal cord has only 62 nerves - by 31 on each side.

Departments and segments of the spinal cord and spine are not at the same level due to the difference in length (spinal cord shorter spine).

This should be considered when comparing the brain segment and the vertebra number during radiology and tomography: if at the beginning of the cervical system, this level corresponds to the vertebral number, and in the lower part it lies on the vertebra above, then this difference has already been in the sacrum and sparrels of the department.

Two important spinal cord functions

The spinal cord performs two important functions - reflex and conductive. Each segment is associated with specific organs, providing their functionality. For example:

• The cervical and chest department - binds to head, hands, chest organs, chest muscles
• Lumbar Division - GTS, Kidneys, Muscular Toolish System
• Sleepy Department - body pelvis, legs

Reflex features are simple reflexes embedded by nature. For example:

• pain reaction - take healing hand if it hurts.
• ball Reflex

This is proved by simple animal experiences. Biologists carried out experiments with frogs, checking how they react to pain in the absence of a head: a reaction was noted both on weak and for severe pain irritants.

Thanks to this conductor, any mental action is carried out:
Stand up, go, take, throw, raise, run, cut off, draw - and many others who have a person, not noticing, makes in their daily life in everyday life and at work.

Such a unique bond between the central brain, the dorsal, the entire CNS and all organs organs and its limbs, as before, remains the dream of robotics.

None, even the most modern robot, is not yet able to carry out the thousandth share of those all possible movements and actions that are subject to bioorganism.

As a rule, such robots are programmed for narrow specialized activities and are mainly used on conveyor automatic industries.

Functions of gray and white substance.To understand how these magnificent spinal cord functions are carried out, consider the structure of the gray and white matter of the brain at the cellular level.

The gray spinal cord substance in the front horns contain the nerve cells of large sizes, which are called efferent (motor) and are combined into five cores:

• central
• frontocel
• rearverteral
• promotional and rearbed

The sensitive roots of small cells of the horses are specific cell processes from sensitive spinal cord assemblies. In the back horns, the structure of the gray substance is heterogeneously.

Most of the cells form their own nuclei (central and chest).

The border zone of the white substance, located near the rear horns, is adjacent to the spongy and pupil zone of the gray substance, whose cells, together with the proceedings of small diffuse scattered cells of the rear horns, form synapses (contacts) with the neurons of the front horns and between adjacent segments. These neurites got the name of the front, side and rear eating beams. The connection of them with the brain is carried out using the conductor paths of the white substance. On the edge of the horns, these bundles form a white cut.

The side horns of the gray substance perform the following important functions:

• In the intermediate zone of the gray substance (lateral horns) there are sympathetic cells of the autonomic nervous system, it is by means of them with the internal organs. The processes of these cells are connected to the front roots
• A spin coat is formed here: at the level of the cervical and upper chest segments there is a reticular zone - a beam from a large number of nerves associated with the zones of activation of the cerebral cortex and reflex activity.

The conductive functions of the white substance are carried out by three cakes - the outer areas bounded by furrows:

• Front rope - a plot between the front median and lateral furrows
• Rear rope - between the rear median and lateral furrows
• Side rope - between frontoolel and rear agent furrows

The axons of the white substance form three conductivity systems:

• short bundles called associative fibers that bind various spinal cord segments
• ascending sensitive (afferent) bundles aimed at brain departments
• descending motor (efferent) bundles directed from the brain to the neurons of the gray substance of the front horns

Ascending and descending pathways.Consider for example Some functions of white substance rope paths:

Front ropes:

• Front pyramid (cortical-spinal) path - Transmission of motor pulses from the cortex of the brain to the cerebrospinal ones (front horns)
• Spinolamic front track - transfer of impulses of touching the skin surface (tactile sensitivity)
• Covenno-cerebral pathway - binding visual centers under the cortex of the brain with the nuclei of the front horns, creates a protective reflex caused by sound or visual stimuli
• Held and Leventhal bundle (predver-spinal path) - fibers of white substance bind vestibular nuclei eight pairs of cranial brain nerves with engine neurons of the front horns
• Stretch rear beam - Combining the upper segments of the spine with the brain barrel, coordinates the work of the eye muscles with the cervical and others.

The rising paths of the side cords are carried out impulses of deep sensitivity (sensations of their body) on cortical-spinal, spinatelamic and cooked-cerebrospinal routes.

Downlink ways of side cordics:

• Lateral cortical-spinal (pyramid) - transfers the pulse of movement from the cortex of the brain to the gray substance of the front horns
• Red-cerebral pathway (There is ahead of the lateral pyramidal), the neighboring rear rear and the spinnotelamic side path are adjacent to it. The special-purpose-cerebrospinal path carries out automatic control of movements and muscle tone at the subconscious level.

In different spinal cord departments, various ratios of gray and white brainstatons. This is explained by different ascending and descending paths. In the lower spinal segments larger than the gray substance.

As you move upwards it becomes less, and the white substance is added to the contrary, as new rising paths are added, and at the level of the upper neck segments and the middle part of the chest white - the most.

But in the area of \u200b\u200bboth cervical and lumbar thickening, the gray substance prevails.

As you can see, the spinal cord has a very complex structure.

The connection of the nerve beams and fibers is vulnerable, and serious injury or disease are able to break this structure and lead to a violation of conductive paths, which is why the point of "cliff" conductivity can be a complete paralysis and loss of sensitivity. Therefore, with the slightest dangerous signs of the spinal cord, it is necessary to examine and in time to treat.

Puncture of spinal cord

To diagnose infectious diseases (encephalitis, meningitis, etc. Diseases), the puncture of the spinal cord is used (lumbar puncture) - the needle in the cerebrospinal channel.

It is carried out in this way:
In the subarachnoid spinal cord space at the level below the second lumbar vertebra, the needle is introduced and the reinforcement fluid (liquor) is taken.

This procedure is safe, since below the second vertebra in an adult, the spinal cord is absent, and therefore there is no threat to his damage.

However, it requires special care, so as not to be taken under the shell of the spinal cord infection or epithelial cells.

The puncture of the spinal cord is carried out not only for diagnosis, but also for treatment, in such cases:

• introduction of chemotherapeutic medicines or antibiotics under the brain shell
• for epidural anesthesia during operations
• for the treatment of hydrocephalus and reducing intracranial pressure (removal of excess liquor)

The puncture of the spinal cord has such contraindications:

• stenosis of the spinal canal
• displacement (dislocation) of the brain
• dehydration (dehydration)

Take care of this important organ, engage in elementary prevention:

1. Take antivirus drugs during the epidemic of viral meningitis
2. Try not to arrange picnics in the forest park zone in May-early June (the period of activity of the encephalitic tick)
3. After each hike in the forest, inspect the whole body, and at the very first signs of the disease, go to the doctor. Signs Such: Headache, High Temperature, Neck Rigidity (Motion Lack), Nausea.

Source: https://zaspiny.ru/raznoye/spinnoy-mozg.html.

The structure and function of the spinal cord

The spinal cord is a complex and multifaceted organ in the nervous system.

In humans, it is controlled and controlled by centers of the brain and has a dependent character. The spine man protects the brain substance from external influence.

The spinal cord features two. Let's consider in more detail what functions it performs.

Characteristic organ

The morphofunctional characteristic of the spinal body is as follows:

The spinal cord consists of two symmetrical half, separated by a deep middle gap. Behind them is separated by the connecting and wanted partition.

Inside the body has a dark area, which is called a gray substance. In the region of the periphery of the spinal cord there is a bright white substance.

From the side of the cross section, the organ has a H-shaped gray matter. Places in which the gray substance is called horns. They are front (ventral), rear (dorsal) and side (lateral).

The gray substance includes neuron bodies, messenger and thin myelin fibers, as well as neuroglia. It differs from white substance by what has multipolar neurons in its composition.

Longitudinal myelin fibers are white substance. Of the nerve fibers that bind different parts of the nervous system, consist of a spinal cord path.

The neurons of the organ are divided into neurites, root cells, as well as internal and beam neurons.

Each rear rog includes a sponge layer, gerological substance, a core of a horn and a chest core.

In the back horn is a student substance that inhibits the work of the spinal cord.

The front horns are equipped with large neurons of the spinal cord, which are formed by the kernels - somatic centers, also they have medial and lateral groups of motor cells. Medial cells are responsible for the functioning of the muscles of the human body, and the lateral - muscles of the hands and legs.

What is the authority?

The spinal cord has round departments, but its structure also includes thickened areas that have a flattened form in front.

The cervical thickening can be seen near the third cervical and first breast vertebra. In the region of 10 - 12 breast vertebrae is a lumbar-sacacon thickening.

In the area of \u200b\u200bsomatic neurons, which are located in the thickening of the organ, there are many roots with a large number of nerve fibers.

The thickness of somatic neurons is the greatest, as they are larger than the remaining neurons.

The spinal cord supplies internal organs and skeletal muscles of the person with nerve fibers that are associated with the CNS. The valuable organ of the spine consists of 31 segments that are responsible for different organs and parts of the body:

For his head, neck, chest cavity, heart, light and hands answer eight cervical segments.

For the abdominal cavity and muscles of the torso, 12 chest and 5 vertebrate segments are responsible.

The muscles of the legs and the lower part of the abdominal cavity control 5 sacral and smoking segment.

The spinal brain fluid can be seen in the channel, which is located in the center of the spinal body.

Functions organ

Thanks to the reflex center, the organ can perform different reflexes. Sensitive pulses through the spinal channel penetrate the brain, transmit information about the status of all spheres in the human body.

The consequences - with the help of descending paths, the impulses that send the brain are transmitted to low-sensitive spinal cord neurons. They activate them and manage the work of neurons.

Reflex function

The organ performs a reflex function: it is responsible for motor and sensual reflexes in the human body. Thanks to the nervous channels, the spinal cord on both sides combines the peripheral organs with the brain.

The substance that is located in the spinal channel provides corresponding signals in the brain. They convey information about the effect on the human body of external and internal environmental factors.

Using the transfer of vegetative reflexes, the CNS authority changes the work of internal life support systems.

The motor function of the spinal cord carries out and regulates the muscle reflexes of the motion system. Neurons that belong to the spinal cord transmit pulses to the muscles that are in the field of hands, legs, body and neck.

The body of the CNS, located in the channel of the spine, takes part in organizing all human movements.

Explore function

The structure of the spinal cord allows you to smoothly transmit pulses through parallel paths to the cerebral cortex of the brain. Some signals are carried out through a short path, and the second - through a long one.

Thanks to the transfer of impulses and reflexes between the organs of the entire human body, it is able to perceive the information and perform the necessary actions.

Therefore, reflex and conductor functions are closely related to each other and are very important to humans.

If the brain is siled or suffered from the bruise, a spinal shock occurs. Because of this, the excitability of nerve reflexes in the center is sharply reduced, the work of the nervous system is slowed down. When spinal shock, factors that awakened reflexes become ineffective.

The consequences, if the spinal canal of the cervical, thoracic or other department is damaged, are as follows:

1. Mine-motor and vegetative reflexes are lost.
2. Reduced pressure.
3. There are no vascular reflexes.
4. Violates the ability to go to the toilet.

Such consequences are dangerous to human life, so the victim should immediately show a doctor to provide the necessary medical care.

What will happen if the functions are broken?

The spinal cord can break or atrophy. In any situation, the patient urgently needs to be delivered to the hospital.

Rule organ

When breaking the body, very unpleasant, heavy and unpredictable consequences may occur.

When the brain is breaking, the sensitivity, human activity is lost, partial or complete body paralysis can occur.

The consequences of the spinal cord breaks are manifested in the receipt by a person partial or complete disabilities, because of which he is not able to independently serve himself and live still.

Such a gap happens upon receipt of household injury, when falling from a height or ingress into a car disaster. If the whole organism refuses to work, a spinal shock occurs, which often leads to the death of a person.

Atrophy organ

In atrophy of the spinal cord, nerve fibers and cells gradually die out, which is why nervous connections are destroyed. Any spinal portion can atrophy.

Such a phenomenon most often occurs in women after 50 years. They become weak. If the disease is diagnosed in children, it means it was inherited.

The consequences in the form of atrophy of the spinal body depends on which his department is suffered. At first, the person becomes less active and sluggish.

Then, moral norms are ignored. After that, problems with memory, speech, senses, motility are beginning.

A person ceases to analyze and express his opinion.

To reduce the consequences and help a person with an atrophied brain to live further, it is recommended to be treated with vitamins and drugs for vessels.

Also for sick people are careful and love of others. It is necessary that the person will take an active part in his life.

It needs to be sent to a certain direction, monitor its regime, nutrition and health.

As you can see, the spinal cord takes part in managing the whole body, as well as in the transfer of information from external factors to the relevant authorities so that they fulfill their functions.

It is important to take care of the body, to treat the disease in a timely manner and follow your health carefully.

Proper nutrition, an active lifestyle, compliance with caution measures, good mood will help the spinal cord better function.

Source: http://drpozvonkov.ru/pozvonochnik/medullae-spinalis/spinnoy-mozg-funktsii.html.

Spinal cord - where is located, length and segments, danger of damage and injuries

The central nervous system organ is a spinal cord that performs special functions and has a unique structure.

It is located in the spinal column, in a special channel, directly connected to the brain.

Functions of the organ - Explorer and reflex activity, it ensures the operation of all parts of the body at a given level, impulses and reflexes transmits.

What is a spinal cord

Latin brain name Spinal Medulla Spinalis. This central organ of the nervous system is located in the spinal canal.

The boundary between it and the brain passes approximately at the intersection of the pyramid fibers (at the level of the nape), although it is conditional. Inside there is a central channel - the cavity protected by soft, bypass and solid cerebral shells.

There is a spinal fluid between them. Epidural space between the outer shell and the bone is filled with adipose tissue and veins grid.

The segmental organization is distinguished by the structure of the spinal cord of a person from other organs. This serves to communicate with the periphery and reflex activity.

It is an organ inside the spinal canal from the first cervical vertebra to the second lumbar, while maintaining the curvature.

From above, it begins the oblong department - at the level of the nape, and at the bottom - ends with a conical polarity, the terminal thread from the connective tissue.

The organ is characterized by the longitudinal segmentality and significance of the links: the front root threads (axons of nervous cells) are out of the protochetral furrow (axons of nervous cells), forming the front motor spher, which serves to transmit motor pulses. Rear root threads form rear root, conductive pulses from the periphery to the center. Side horns are equipped with motor, sensitive centers. The roots create a spinal nerve.

Length

In an adult, an organ in length is 40-45 cm, equal to 1-1.5 cm in width, weighing 35 g.

It increases in the bottom of the bottom up, the largest diameter reaches the top cervical (up to 1.5 cm) and the lower lumbar-sacrive (up to 1.2 cm).

In the chest area, the diameter is 1 cm. The organ produces four surfaces:

• flattened front;
• convex rear;
• two rounded side.

Appearance

On the front surface along the entire length, the median gap is running, which has a fold of the brain shell - an intermediate cervical partition.

Behind the middle groove, connected to the gliose fabric plate. These gaps divide the spinal pole into two halves, connected by a narrow cloth bridge, in the center of which is the central channel.

From the sides, too, there are furrows - anterior and rear agent.

Spinal cord segments

The spinal cord departments are divided into five parts, the value of which depends not on the location, and on which the emerging nerves leave the vertebral channel. In total, a person can have 31-33 segments, five parts:

• the cervical part is 8 segments, at its level greater than gray substance;
• breast - 12;
• lumbar - 5, second area with lots of gray substance;
• sacral - 5;
• copchicker - 1-3.

Gray and white substance

On the section of symmetrical half, a deep median slot is visible, a connective wanted partition. The inner part is darker - this is a gray substance, and on the periphery is lighter - white substance.

In cross section, the gray substance is represented by the drawing of the "butterfly", and his protrusions resemble the horns (front ventral, rear dorsal, lateral lateral). Most of the gray substance on the lumbar department is less - on breast.

In the brain cone, the entire surface is made with gray, and along the periphery is a narrow layer of white.

What is formed by a gray substance of the spinal cord - it consists of bodies of nerve cells with processes without myelin shell, thin myelin fibers, neuroglia. The basis is the multipolar neurons. Cells lie inside with nuclei group:

• root - axons leave as part of the front roots;
• internal - their processes end with synapses;
• beams - axons pass to the white substance, carry nerve impulses, form conductive paths.

Between the rear and side horns, gray is hung inside the white, forming a sequencing burst - mesh education.

The functions of a gray substance CNS serve: transmission of pain impulses, information about temperature sensitivity, closure of reflex arcs, obtaining data from muscles, tendons and ligaments. Neurons of the front horns are involved in the connection of the divisions.

White substance functions

A complex system of myelin, messenger nerve fibers is a white substance of the spinal cord.

There is a supporting nervous fabric - neuroglia, plus blood vessels, a slight amount of connective tissue. Fibers are collected by bunches that communicate between segments.

White substance surrounds gray, conducts nerve impulses, performs mediation.

The functions of the spinal cord

The structure and functions of the spinal cord are directly connected. Allocate two important tasks of the organ operation - reflex, conductive.

The first is the fulfillment of the simplest reflexes (pulling the hands with a burn, the extension of the joints), the connections with skeletal muscles.

The conductor transmits pulses from the spine to the brain, back to the ascending and descending paths of movement.

Reflex

A reflex function consists in the response of the nervous system to irritation. It includes pulling hands when cooked, cough when foreign particles get into the throat.

Irritation from the receptor on the pulse enters the inside of the spinal channel, switches the motor neurons that are responsible for the muscles cause them to reduce them.

This is a simplified scheme of the reflex ring (arc) without the participation of the brain (person does not think when performing an action).

Regenerate reflexes (breast sucking, breathing) or purchased. The first helps to identify the correctness of the elements of the arc, the segments of the body. They are checked with neurological inspection.

The knee, abdominal, the plantar reflex is mandatory to test human health.

These are superficial species, deep reflexes include bend-elbow, knee, achilles.

Conductor

The second function of the spinal cord is a conductor, which transmits pulses from the skin, mucous membranes and internal organs in the brain in the opposite direction. The white substance serves as a conductor, carries information, impulse on exposure from the outside.

Due to this, a person receives a certain feeling (mild, smooth, slippery object). In the loss of sensitivity, the feeling of touch to something can not be formed.

In addition to the commands, the impulses transmit data on the position of the body in space, pain, muscle tension.

What human bodies control the work of the spinal cord

Responsible for the spinal channel and managing the entire work of the scorn's brain is the main body of the central nervous system - the brain.

Assistants are numerous nerves and blood vessels. The brain has a big impact on the care of the dorsal - controls walking, running, labor movements.

With the loss of communication between the authorities, the person in the end is practically becoming helpless.

Danger of damage and injuries

The brain of the dorsal binds all organism systems. Its structure plays an important role to perform the correct operation of the musculoskeletal system.

If it is damaged, a spinal injury will arise, the severity of which depends on the vastness of damage: stretching, breaking bundles, dislocation, damage to discs, vertebrae, processes are light, medium.

Heavy believes with displacement and multiple damage to the channel itself. It is very dangerous, leads to a violation of the functionality of the cakes and paralysis of the lower extremities (spinal shock).

If the injury is heavy, shock lasts from several hours to months. The pathology is accompanied by a disturbance of sensitivity below the injury and dysfunction of pelvic organs, including urinary incontinence.

Research injuries can computer-resonant tomography. To treat light bruises and damage to zones, medications, medical gymnastics, massage, physiotherapy can be used.

Heavy options need operation, especially the diagnosis of compression (the gap - cells die instantly, there is a risk of disability).

The consequences of the injury of the brain of the dorsal are a long recovery period (1-2 years), which can be accelerated by iggoreflexotherapy, ergotherapy and other interventions.

After a severe case, there is a risk of returning the motor ability not completely, and sometimes remain in a wheelchair forever.

The structure of the spine and brain. The nervous system is divided into the central, located in the skull and the spine, and the peripheral, outside the skull and the spine. The central nervous system consists of a spinal and brain.

Fig. 105. Nervous System (Scheme):
1 - big brain, 2 - cerebellum, 3 - cervical plexus, 4 - shoulder plexus, 5 - spinal cord, 6 - sympathetic barrel, 7 - Breast nerves, 8 - middle nerve, 9 - solar plexus, 10 - radiation nerve, 11 - Locking nerve, 12 - lumbar plexus, 13 - Sleeping plexus, 14 - Copier plexus, 15 - female nerve, 16 - Sedalnaya nerve, 17 - Tibial nerve, 18 - Malobers

The spinal curtain is a long severity having an approximately cylindrical shape and located in the spinal canal. At the top it gradually goes into an oblong brain, downstairs ends at the level of the 1st lumbar vertebrae. There are 2 thickening to the upper and lower extremities on the site of nerves to the upper and lower limbs: the cervical - at the level of the 2nd cervical to the 2nd breast vertebrae and the lumbar - from the level of the 10th thoracic with the highest thickness at the level of the 12th breast vertebra. The average length of the spinal cord in a man is 45 cm, a woman has 41-42 cm, the average weight - 34-38 g.

The spinal cord consists of two symmetric half, connected by a narrow jumper, or a spike. On the cross-section of the spinal cord it is clear that in the middle there is a gray substance consisting of neurons and their processes, which distinguishes two large widespread horns and two narrower rear horns. In the chest and lumbar segments there are still side protrusion, side horns. In the front horns there are motor neurons, from which centrifugal nerve fibers are deployed, forming the front, or motor, roots, and through the rear roots in the horn, the centripetal nerve fibers of the neurons of the spinal nodes are included. Blood vessels are also located in the gray substance. 3 main neurons groups are distinguished in the spinal cord: 1) large motors with long small axons, 2) forming the intermediate zone of the gray substance; Acids them are divided into 2-3 long branches, and 3) sensitive, included in the composition of spinal assemblies, with highly branching axons and dendrites.

The gray substance is surrounded by white, which consists of longitudinally located meal and part of cinema nerve fibers, neuroglia and blood vessels. In each half of the spinal cord, the white substance is separated by the horns of the gray substance into three columns. White substance located between the front furrow and the front horn is called front pillars, between the front and rear horn - the side pillars, between the rear jumper and the rear horn - the rear pillars. Each pillar consists of separate beams of nerve fibers. In addition to thick meal fibers of motor neurons, thin roots of the side roots belonging to the autonomic nervous system are extended along the front roots belonging to the vegetative nervous system. In the rear horns there are inserts, or beam, neurons whose nerve fibers are connected to each other motor neurons of different segments and are part of the beams of white substance. Meal of nerve fibers are divided into short - local spinal cord paths, and long-long conductive paths connecting the spinal cord with the head.

Fig. 106. The transverse cut of the spinal cord. Scheme of conductive paths. On the left are ascending, on the right - downward paths. Rising ways:
/ - gentle beam; Xi - a wedge-shaped beam; X - rear spinal cerebelling path; VIII - front spinal path; IX, VI - side and front spin-butlamic paths; XII - the spinal flow path.
Descending ways:
II, V - side and front pyramidal paths; III - Rubrost Path; IV - Vestibulo-spinal path; VII - Olive Path.
Circles (without numbering) indicated paths connecting the spinal cord segments

The ratio of gray and white substance in different segments of the spinal cord is not equally. Lumbar and sacral segments contain due to a significant decrease in the content of nerve fibers in the descending paths and the beginning of the formation of the rising paths greater than the gray substance than which white. In the middle and especially the upper chest segments of the white substance relatively more than gray.

In the neck segments, the amount of gray substance increases and is significantly increasing white. The thickening of the spinal cord in the cervical department depends on the development of the innervation of the muscles of the hands, and the thickening of the lumbar department - from the development of the innervation of the muscles of the legs. Consequently, the development of the spinal cord is due to the activities of skeletal muscles.

The supporting base of the spinal cord is neuroglia and penetrating in a white substance connecting layers of a soft cerebral shell. The surface of the spinal cord is covered with a thin neuroglial shell, in which blood vessels are located. Outside, the spiny shell of the loose connective tissue is connected to it, in which the spinal fluid circulates. The spider shell is firmly adjacent to the outer solid sheath of dense connective tissue with a large number of elastic fibers.

Fig. 107. The scheme of the location of the spinal cord segments. The location of the spinal cord segments is shown in relation to the corresponding vertebrae and the place of the reserves of the spine from the spine canal

The spinal cord of a person consists of 31-3 of 33 segments, or segments: cervical - 8, breast - 12, lumbar - 5, sacrals - 5, cockerel-1-3. From each segment there are two pairs of roots connecting into two cerebral nerves consisting of centripetal - sensitive and centrifugal - motor nerve fibers. Each nerve begins at a certain spinal cord segment with two roots: front and rear, which end at the spinal assembly and, connecting together the duck from the node, form a mixed nerve. Mixed spinal nerves extend from the spinal channel through the intervertebral holes, except for the first pair passing between the edge of the occipital bone and the upper edge of the 1st cervical vertebra, and the spherian root - between the edges of the spacing spine. The spinal cord is shorter than the spine, so there is no correspondence between the spinal cord segments and vertebrae.

The spinal nerves innervate the skin and muscles of the body, hands and legs. They form: 1) cervical plexus consisting of 4 upper cervical nerves, innervating neck skin, nape, ear shell and skin on the clavicle, neck muscles and aperture; 2) shoulder plexus of 4 lower cervical nerves and 1 thoracic, innervating skin and muscles of the shoulder belt and hands; 3) breast nerves that correspond to 12 breast spinal cord segments and innervate the skin and muscles of the chest and abdomen (front branch) and the skin and muscles of the back (rear branch), therefore, the chest spinal nerves have a proper segmental location and are clearly divided into the front - abdominal part and rear - the dorsal part; 4) lumbar plexus consisting of 12th breast and 4 upper lumbar nerves, innervating skin and part of the muscles pelvis, hips, legs and feet; 5) Personal plexus, consisting of lower lumbar, sacrats and cockerel nerves, innervating skin and other muscles pelvis, hips, legs and feet.

Fig. 108. Head Brain, Middle Surface:
I - the frontal share of the big brain, 2 - the parietal share, 3 - the occipital proportion, 4 - the corn body, 5 - cerebellum, 6 - the auditorium (intermediate brain), 7 - pituitary , 10 - Varoliev Bridge, 11 - oblong brain

The brain also consists of a gray and white substance. The gray matter of the brain represents a variety of neurons, which are grouped into numerous clusters - nuclei and covering various brain departments. In total, there are approximately 14 billion neurons in the human brain. In addition, the composition of the gray substance includes neuroglia cells, which are approximately 10 times more than neurons; They make up 60-90% of the entire mass of the brain. Neuroglia is a supporting tissue that supports neurons. It also participates in the exchange of substances of the brain and especially neurons, hormones and hormone-like substances are formed in it (neurosception).

The brain is divided into an oblongable brain and Barolic Bridge, the cerebellum, the middle brain and the intermediate brain, which make up its barrel, and the end brain, or large hemispheres that cover the brain barrel from above (Fig. 108). In humans, in contrast to animals, the volume and weight of the brain sharply dominated over the spinal cord: about 40-45 times or more times (chimpanzee is the brain weight exceeds the weight of the spinal only 15 times). The average weight of the adult brain is approximately 1400 g in men and due to a relatively smaller average body weight about 10% less in women. The mental development of a person does not directly depend on the weight of its brain. Only in cases where the brain weight of the Men is below 1000 g, and the women below 900 g, the structure of the brain is disturbed and mental abilities are reduced.

Fig. 109. The front surface of the brain barrel. The beginning of the cranial nerves. Lower cerebellum surface:
1 - optic nerve, 2 - island, 3 - pituitary glands, 4 - cross-nerves, 5 - funnel, 6 - gray hill, 7 - downtown body, 8 - pits between legs, 9 - brain leg, 10 - semi-lunar knot, 11 - Little Further True Nerva, 12 - Large Truppy Nerva Forest, 13 - Tarrow Nerve, 14 - Language nerve, 15 - Vascular plexus IV ventricle, 16 - Venting nerve, 17 - Additional nerve, 18 - First cervical nerve, 19 - Piramid Cross , 20 - Pyramid, 21 - Podium-speaking nerve, 22 - hearing nerve, 23 - Intermediate nerve, 24 - Facial nerve, 25 - Truhnaya nerve, 26 - Varoliev Bridge, 27 - Blood nerve, 28 - Outdoor crankshaft, 29 - Overall nerve , 30 - visual way, 31-32 - frontforced substance, 33 - outer olfactory strip, 34 - olfactory triangle, 35 - olfactory tract, 36 - olfactory bulb

12 pairs of cunning nerves are emerging from the cerebral core barrels, which, unlike the spinal surge, do not have the right segment output and clear division on the abdominal and spinal part. Capnot nerves divide on: 1) olfactory, 2) visual, 3) Overall, 4) block, 5) triple, 6) discharge, 7) facial, 8) auditory, 9) Language, 10) wandering, 11) add, 12 ) Subject.

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The spinal cord lies in the spinal canal and is an adult for a 41-45 cm long, a somewhat flattened front. At the top, it directly goes into the brain, and at the bottom ends with a conical polarity, from which the end thread moves down. This thread goes down to the sacral canal and is attached to its wall.

Structure

The spinal cord has two thickening: cervical and lumbar, corresponding to sites from it from the nerves going to the upper and lower limbs. The front and rear longitudinal grooves divide the organ into two symmetrical half, each in turn has two weakly pronounced longitudinal furrows, of which the front and rear roots go - spinal nerves. The location of the roots does not correspond to the level of intervertebral holes and roots, before exiting the channel, are sent to the sides and down. In the lumbar department, they go parallel to the terminal thread and form a bunch, which is the name of the horse-tail.

From the spinal cord, forming from the front (motor fibers) and the rear (sensitive fibers) of the roots, 31 pairs of mixed spinal nerves depart. The area corresponding to the dishevement of the pair of cerebrospinal nerves is called the nervous segment, or the spinal cord segment. Each segment innervates certain skeletal muscles and skin sections.

The cervical and upper chest segments innervate the muscles of the head, the belt of the upper extremities, the organs of the chest, heart and lungs. Bottom breast segments and part of the lumbar are responsible for managing the muscles of the body and intra-abdominal organs. The nerves to the lower limbs and partly to the abdominal cavities are departed from the lower lumbar segment and the sacrum.

Structure of gray substance

The transverse cut of the spinal cord has the form of a butterfly, which is formed by a gray substance surrounded by white. The wings of the butterfly are symmetric areas in which the front, rear and side pillar (or horns) are distinguished. Front horns wider than the rear. The rear roots enter the rear horns, and the front roots come out of the front horns. In the center of the gray substance, there is a channel where the canal circulates the liquor, which supplies the nervous tissues with nutrients.

The gray substance is formed from more than 13 million nerve cells. Among them, three types are distinguished: root, bundled, insert. The composition of the front roots includes axons of root cells. Beam cell processes combine the spinal cord departments among themselves, and inserts end with synapses within the gray substance.

Neurons with a similar structure are combined into the spinal cord nucleus. In the front horns, ventromedual, ventrolateral, domdomal and central pairs of cores are distinguished, in the back horns - their own and chest. In lateral horns there is a lateral intermediate core formed by associative cells.

The structure of the spinal cord

White substance structure

White substance consists of processes and beams of nerve cells that form a conductive system of the organ. The permanent and unhindered transfer of impulses is provided by two groups of fibers:

1. Short bundles of nerve endings that occupy different levels of the spinal column are associative fibers.
2. Long fibers (projection) are divided into ascending, which go towards large hemispheres, and descending - go from the hemispheres to the spinal cord.

Conductive paths

Long ascending and descending paths using double-sided communications connect the periphery with the brain. The afferent pulses according to the conducting paths of the spinal cord are carried out in the head, transmitting information about all changes in the external and inner environment of the body. According to the downward paths, the pulses from the brain are transmitted to the effector neurons of the spinal cord and cause or regulate their activities.

Rising ways:

1. Rear cores (sensitive ways) that conduct signals from skin receptors to the oblong brain.
2. Spinolamic, guide pulses in Talamus.
3. Dorsal and ventral (spin-plated) are responsible for carrying out excitement from proproporeceptors to the cerebellum.

Downward paths

1. Pyramid - passes in the front and side pillars of the spinal cord, is responsible for performing movements.
2. The extrapyramida tract begins on the brain structures (red core, basal ganglia, black substance) and goes to the front horns, responsible for involuntary (unconscious) movements.

Spinal cord shells

The organ is protected by three shells: solid, pausto and soft.

1. The solid shell is outside the spinal cord, and does not fit tightly to the walls of the spinal canal. Educated space is called epidural, there is a connecting tissue. Below is the subdural space on the border with a spider shell.
2. The cute shell consists of loose connective tissue and separated from a soft shell with subarachnoid space.
3. The soft shell directly covers the spinal cord, limited from it only a thin glial membrane.

Blood supply

The front and rear spinal arterys descend along the spinal cord and are connected to each other many anastomoses. Thus, a vascular network is formed on its surface. Also, central arterys are departed from the front spinal artery, which penetrate the spinal cord substance near the anterior spike. Blood supply by 80% comes from the front spinal artery. The venous outflow is carried out through the elements of the veins flowing into the internal vertebrate venous plexuses.

Functions

The functions of the spinal cord

The spinal cord is inherent in two functions: reflex and conductive.

As a reflex center It carries out complex motor and vegetative reflexes, and is also a place of closure of reflex arcs, which consist of three links: afferent, inserted and efferent.

It is associated with receptors, and efferent (motor) with muscles and internal organs, afferent (sensitive) paths.

An example is congenital and acquired human reflexes, they will be closed at different levels of the spinal cord: the knee at the level of the 3-4 lumbar segment, the achilles is 1-2 sacral segment.

Conductor The function is based on the transfer of pulses from the periphery (from the skin receptors, mucous, internal organs) in the cerebral on the rising paths and backwards.

Similarities and differences in brain and spinal cord

The brain barrel is a structure into which the spinal cord passes through the occipital hole, and has a similar structure of it. The similarity lies in the performance of reflex and conductor functions.

They are distinguished by the arrangement of the gray matter: for the brain trunk, a gray substance is characterized in the form of cores, which are responsible for vital functions: breathing, blood circulation, etc., and in the dorsal - it goes in the form of columns. Also, the trunk is an autonomous substance in the regulation of sleep, vascular tone, consciousness, and the dorsal carries out all actions under the control of the brain.

The spinal cord is an important link of the nervous system, connecting organs and parts of the human body together, providing adequate interaction with the world. This complex biological mechanism organizes the realization of the vital functions, working in close connection with the head centers. Damage to any area of \u200b\u200bthe spinal cord will entail serious health effects.

Location, external structure

The spinal cord is located in the spinal canal, composed of voids of the vertebrae. Its reliable protection and fixation is provided by a multi-layer shell (a dural bag).

The location of the spinal cord - from the nape to the second vertebra of the lumbar sector. Externally navigate, where a person is located in a person, it is possible at the top point of the first vertebra, as well as on the lower edge of the ribs. The length of the spinal cord among male representatives is 45 cm, in women's - from 42 to 43 cm.

The external structure of the spinal cord is a thick tapering cord (litter) with two pronounced broadenings.

The overall diagram of the spinal cord device under vertebrae is as follows (from the nape):

• medulla;
• pyramidal area;
• cervical thickening;
• lumbosacral broadening;
• cone (transition area to thread);
• the thread that fastens with the tailbone, ending in the area of \u200b\u200bthe 2nd vertebra of the Copshing Department.

The interaction of the head centers with the head is provided by the bridge localizing in the occipital region.

Shell, Combine Spaces

How is the spinal cord? From the outside, it will be incomplete without a description of the surrounding dural bag that copies the form of the spine.

Human spinal cord shells are three separate layers around the central channel: soft, web and solid. The solid shell of the spinal cord is formed by a connective tissue of strong fibers. The preservation of the spatial position is ensured by fixation to the edges of the intervertebral holes, special traps (dorsal, lateral) bind fabrics with the surface of the vertebral canal surface. The solid shell separates from the middle (web) subdural space.

Spinal cord casing - intermediate layer of a fool bag. Here are the nerve roots, the brain itself, which is fenced from the walls of the shell with subarachnoid space filled with liquid (liquor). The web layer is very dense, but thin. Posted by cellular connective tissue.

Soft (vascular) sheath is smashed with a brainstant. The fabric is woven with bunches of collagen fibers, forming outdoor and internal circular layers. They are located a thick network of blood vessels.

Along the soft shell placed a number of gear plates. On the one hand, they are laughing with the brain itself in the area between the rear and front roots, on the other, with a spider shell, and through it - with a firm, acting in the role of a kind of through fastener. The additional connection of the shells and the combustinal spinal cord spaces provide nerve roots.

The main functions of the spinal cord shells are protective and trophic (blood flow control).

The liquid in the inter-bore spaces protects the nerve fabrics from oscillations, shake, takes an active part in metabolic processes, reducing metabolic products.

Functions

The physiological needs of a person sells thanks to the unique structure and the functions of the spinal cord, without thinking that this is this body and what the principles of his work.

The main functions of the spinal cord include:

1. Reflex. Provides muscle reaction to external irritation (tactile, thermal, acid, pain reflexes), movement of skeletal muscles, vessels, rectum, urogenital system.
2. Conductive. The human spinal cord is the translator of external signals to the head center and from it. The conductor function of the spinal cord is ensured by the relationship of consciousness and reflexes.
3. The tonic function of the spinal cord supports the minimum muscles voltage at rest (muscular tone).
4. Endocrine. The central spinal channel was lined with a special layer of cells - edendimogly. In young people, they produce bioactive substances regulating sexual function, blood pressure, daily rhythms.

What are the spinal cord functions (main), briefly described in Table 1.

Table 1

The violation of the functioning of the nerve tissues is almost always associated with partial or complete loss of legal capacity.

Internal structure

The body located in the brain spine is composed of various types of nerve cells and fibers forming innervating muscles and root organs, as well as conductive paths for external and internal pulses.

Thickening and furrows

The internal structure of the spinal cord is consisted of several sectors formed by longitudinally located deepening:

• front median gap, passing along the entire front part;
• middle furrow, separating the back surface on 2 equal half;
• over the sides of the front median cracks are opposite of grooves;
• on both sides of the rear agent of the middle grooves.

As a result, it turns out to be divided 2 halves (in the jumper - the central spinal channel), each of which consists of 3-sections of the cakes:

• between the rear median and rear-legally furrows - the rear rope;
• between rear-latheral and frontwateroral - side;
• between the anterior median slit and an opposite groove - front.

Externally, the codes resemble the long bulk rollers constituting the body of the tight.

Gray and white substance

The central channel (the remainder of the nervous tube) is surrounded by a gray spinal cord substance, on the cross section similar to the butterfly (the letter "H"). The lower part is the front horns (wide, short, thick), the top - the rear horns of the spinal cord (narrow, elongated). Along the channel on the site from the last cervical segment to the first lumbar, the side horns (pillars) are drawn to the first lumbar.

The composition of the gray substance includes multipolar nerve cells (neurons) and fibers. Neurons consist of a body (catfish, pericarion), around which short branching (dendrites) and a long process (axon) are growing. Dendriti caught pulses, broadcast them into the body of the neuron, and from there the signal is transmitted to the tissue through axons.

Types of neurons:

• root. The neuron processes go beyond the shells of a fool bag, reach muscle fibers, where synapses are formed (the place of contact of neurons and cells receiving the signal);
• internal. Axons are within the gray substance;
• puchow. Their processes form conductive paths to the thickness of the white substance.

According to functions, the following types of neurons distinguish:

• sensitive (form lateral codes);
• vegetative (part of the front roots);
• associative (form internal segments);
• motor (directed to muscle fibers).

Diffusedly scattered gray cells provide internal connections, some are grouped into the spinal cord nucleus.

From above, the gray substance is surrounded by white, providing the conductivity of the formed signals.

The white substance consists of longitudinally lying nerve fibers of three types:

• short bundles connecting brain structures;
• afferent long (sensitive);
• efferent long (motor).

The connection between the gray and white substance is provided by glii - a layer of cells that serves as a layer between neurons and capillaries.

Koreshki

The roots of the spinal nerves are formed by the axons of nerve cells. 2 types are separated: front and rear. The front spinal cord roots grow longitudinal rows from the front side groove. Compiled by the process of motor neurons from the nuclei of the front and partially lateral horns of the gray substance. The rear are formed from the processes of sensitive neurons in the spinal nodes (in intervertebral openings). They come through the back side groove. The front and rear roots at the outlet of the fool bag merge into the spinal nerve, forming a short barrel, which disintegrates into 2 branches (receiving signal and executing).

In case of damage to the rear (sensitive) roots disappears the ability to touch the sections tied to them. If the front roots are crossed or transmitted, it occurs with paralysis of the corresponding muscles.

To date, it is determined how much the roots of the spinal nerves departs from the spinal cord - 31 steam.

Conductive paths

Conductive spinal cord paths provide internal intersectoral signal broadcast and communications with the head center in both directions. The ascending pathways of the spinal cord are formed by subtle and wedge-shaped beams of afferent fibers located in the rear and side cords (throughout the length of the length of the tight). The excitation arising in the receptors of organs and skin as a reaction to the external stimuli is transmitted by nerves into the rear roots, processed by neurons of the spinal nodes. From here the signal goes to the headpartmental or in the cells of the rear horns.

The descending paths of the spinal cord are composed of the beams of efferent fibers of the front and side cords heading into the front horn of the gray substance. Fibers transmit a signal from the head center to the motor neurons of the dorsal, where the information goes on to the addressee organ.

Thus, a reflex arc is formed, represented by three types of neurons:

• sensitive, perceive external signal and conducting it in their processes;
• inserts forming synaps with axon of sensitive cells and transmitting a signal for its processes to the front horns;
• motor (in the front horns), which take information from inserted cells into their bodies and in the axon in the composition of the front roots is broadcast by its muscle fibers.

There are several ways for which nerve impulses pass. They are distributed over innervation zones (signal reception sites).

Segments: Building

The structure of a spinal cord of a person implies its separation along the entire length of structural and functional units - segments:

• 8 cervical;
• 12 chest;
• 5 lumbar and sacral;
• 1 Copchik.

The inner structure of the spinal cord is designed in such a way that each sector has its own region of innervation, which is provided by four spinal roots forming one nerve on each side of the segment.

The designation of the spinal cord segments and their functions are presented in Table 1.

Table 1

Designation	Sector	Innervation zones (dermatomas)	Muscles	Organs
Cervical (cervical): C1-C8	C1		Small muscles of the cervical
	C4.	Purpose, rear side of the neck	Top muscles back, diaphragm muscles
	C2-C3.	Scoping area, neck
	C3-C4.	Included part		Lungs, liver, gallbladder, intestines, pancreas, heart, stomach, spleen, duodenum
	C5.	Neck back, shoulder, shoulder flavor area	Shoulder, forearm flexors
	C6.	Neck back, shoulder, forearm outside, thumb brush	Back top, outdoor forearm and shoulder
	C7.	Back grains, fingers brush	Fields of ray-tank joint, fingers
	C8.	Palm, 4.5 fingers	Fingers
Breast (thoracic): TR1-TR12	TR1	The area of \u200b\u200bthe armpits, shoulders, forearms	Small musculature of brushes
	TR1-TR5			A heart
	TR3-TR5			Lungs
	TR3-TR9.			Bronchi
	TR5-TR11			Stomach
	TR9			Pancreas
	TR6-TR10			Duodenum
	TR8-TR10			Spleen
	TR2-TR6.	Spin from the skull diagonally down	Intercostal, spinal muscles
	TR7-TR9	Front, rear body surfaces to navel	Back, abdominal cavity
	TR10-TR12.	The body is below navel
Lumbar (lumbal): L1-L5	TR9-L2.			Intestines
	TR10-L.			Kidney
	TR10-L3.			Uterus
	TR12-L3.			Ovarian, testicles
	L1	Groin	Abdominal wall below
	L2.	Thigh ahead	Pelvic muscles
	L3.	Hip, goal from the inside	Hip: Flexors, Rotary, Front Surface
	L4.	Thigh ahead, rear, knee	Extensors of the tibia, femoral front
	L5	Shin, fingers stop	Femoral front, side, shin
Sacral (sacral): S1-S5	S1.	Posterior part of the shin and hips, stop outside, fingers	Buttock, shin ahead
	S2.	Buttocks, thigh, shin inside	Genet Behind, Musculature Foot	Livestock, bladder
	S3.	Sender organs	Pyazova, groove muscles, anus sphincter, bladder bladder
	S4-S5.	Rear Passage Region, Crotch		Acts of arbitrary defecation and urination

The spinal cord departments are shifted up with respect to the corresponding vertebral bones. Lumbar segments are significantly lagging behind, so the lower part of the spine is innervated by the descendants of the roes of the roots in the form of a horse-tail. The ratio of segments (necristers), parts of the body and spine (somites) is called skeletopia.

Video

Video - the structure of the spinal cord

Injuries and lesions

The damage to the spinal cord due to injury (injury, compression, gap (hemorrhage), shaking) or illness leads to grave consequences.

Chronic pathology (myelopathy): General symptoms of spinal cord lesions with full mechanical transverse damage:

• below the level of destruction of arbitrary motor reflexes no, skin is also missing;
• no control over the pelvic authorities (arbitrary defecation and urination);
• violation of thermoregulation.

Specific signs of diseases and brain damage depends on the localization of injury.

When squeezing a fool bag of hernias or due to the displacement of the vertebrae, and with the development of diseases there are pains in the back (more often in the neck, lower back). If the conical part is damaged, the pain impulses are localized in the lower section. There is a weakness of the limbs, numbness of certain areas of the body, headaches, migraines, bother with urgent urination, sexual dysfunction.

MRI, CT, the analysis of the liquor (puncture) are used as diagnostic methods. The procedure for taking puncture is carried out under local anesthesia. A thin needle introduced into the intervertebral space under the control of the X-ray apparatus is closed by a small amount of fluid for research.

The treatment of the spinal cord is as difficult as its structure. Therefore, this area of \u200b\u200binjuries should be protected as protective adaptations, prevent infectious lesions, healing the disease in a timely manner (including ORVI, otitis, sinusitis). The state of this unit of the nervous system is largely determined by the integrity of the structure of the spine