Pathways ascending and descending. Major pathways of the brainstem and spinal cord

The nerve cell has a large number of processes. The processes removed from the cell body are called nerve fibers. Nerve fibers that do not extend beyond the central nervous system, form conductors of the brain and spinal cord. Fibers that travel outside the central nervous system gather into bundles and form peripheral nerves.

Nerve fibers passing inside the brain and spinal cord have different lengths - some of them come into contact with neurons located close, others with neurons located on greater distance, while others move far away from the body of their cell. In this regard, three types of conductors can be distinguished that carry out the transmission of impulses within the central nervous system.

1. Projection conductors communicate with the overlying sections of the central nervous system with the sections located below. (Fig. 4). Among them, there are two types of paths. Descending conduct impulses from the overlying parts of the brain down and are called centrifugal. They are motor in nature. The paths that direct from the periphery the conductive impulses from the skin, muscles, joints, ligaments, bones to the center have an upward direction and are called centripetal. They are sensitive in nature.

Rice. 4.

I - posterior spinal bundle; II - fibers of the posterior cord; III - spinal tuberous bundle; IV - anterior cortical-spinal bundle; V - lateral cortical-spinal bundle; VI - vestibulo-spinal bundle

2. Commissural, or adhesive, conductors connect the hemispheres of the brain. Examples of such connections are the corpus callosum, connecting the right and left hemispheres, the anterior commissure, the uncinate gyrus commissure, and the gray commissure of the thalamus, connecting both halves of the thalamus.

3. Associative, or associative, conductors connect parts of the brain within the same hemisphere. Short fibers connect various convolutions in one or closely spaced lobes, and long ones stretch from one lobe of the hemisphere to another. For example, an arcuate bundle connects the lower and middle departments frontal lobe, the lower longitudinal connects the temporal lobe with the occipital. Allocate the fronto-occipital, frontal-parietal bundles, etc. (Fig. 5).

Rice. 5.

I - upper longitudinal (or arcuate) bundle; II - fronto-occipital bundle; III - lower longitudinal beam; IV - waist bun; V - hook-shaped bundle; VI - arcuate fiber; VII - large commissure (corpus callosum)

Consider the course of the main projection conductors of the brain and spinal cord.

centrifugal ways

The pyramidal path starts from large and giant pyramidal cells (Betz cells) located in the fifth layer of the anterior central gyrus and the paracentral lobule. In the upper sections there are paths for the legs, in the middle sections of the anterior central gyrus - for the trunk, below - for the arms, neck and head. Thus, the projection of human body parts in the brain is presented inverted. From the total amount of fibers a powerful bundle is formed, which passes through the inner bag. Then the pyramidal bundle passes through the base of the brain stem, the pons, entering the medulla oblongata, and then into the spinal cord.

At the level of the pons and medulla, part of the fibers of the pyramidal pathway ends in the nuclei of the cranial nerves (trigeminal, abducens, facial, glossopharyngeal, vagus, accessory, hypoglossal). This short bundle of fibers is called the cortical-bulbar pathway. It starts from the lower sections of the anterior central gyrus. Before entering the nuclei, the nerve fibers of the short pyramidal pathway cross over. Another, longer bundle of pyramidal nerve fibers, starting from the upper sections of the anterior central gyrus, descends down into the spinal cord and is called the cortical-spinal path. The latter, on the border of the medulla oblongata with the spinal cord, forms an incomplete decussation, and most of nerve fibers (subjected to cross) continue their way in the lateral columns of the spinal cord, and a smaller part (not crossed) goes as part of the anterior columns of the spinal cord of its side. Both segments end in the motor cells of the anterior horn of the spinal cord.

The pyramidal pathway (cortical-spinal and cortical-bulbar) is the central segment of the path that transmits motor impulses from the cells of the cerebral cortex to the nuclei of the cranial nerves and cells of the spinal cord. It does not go beyond the central nervous system.

From the motor nuclei of the cranial nerves and from the cells of the anterior horns of the spinal cord, the peripheral segment of the path along which the impulse is directed to the muscles begins. Consequently, the transmission of a motor impulse is carried out through two neurons. One conducts impulses from the cells of the cortex of the motor analyzer to the cells of the anterior horns of the spinal cord and to the nuclei of the cranial nerves, the other - to the muscles of the face, neck, trunk and limbs (Fig. 6).

When the pyramidal tract is damaged, movements are disturbed on the side opposite to the lesion, which can be expressed by a complete absence of muscle movements (paralysis) or their partial weakening (paresis). Depending on the location of the lesion, there are central and peripheral paralysis or paresis.

Rice. 6.

I - cortical-spinal bundle; II - cortical-bulbar bundle; III - the crossed part of the cortical-spinal bundle; IV - uncrossed part of the cortical-spinal bundle; V - cross of pyramids; VI - caudate nucleus; VII - hillock; VIII - lentil kernel; IX - pale ball; X - leg of the brain; XI - varolian bridge; XII - medulla oblongata; K. VII - core facial nerve; K. XII - core hypoglossal nerve

The Monakovic bundle begins in the midbrain from the red nuclei. Immediately upon exiting the red nucleus, the fibers cross and, having passed the hindbrain, descend into the spinal cord. In the spinal cord, this bundle of nerve fibers is located in the lateral columns near the bundle of the crossed pyramidal tract and gradually ends, like pyramidal path, in the cells of the anterior horns of the spinal cord.

Monakov's bundle conducts motor impulses that regulate muscle tone.

The roof-spinal bundle connects the anterior colliculus of the midbrain with the anterior and partly lateral columns of the spinal cord. Participates in the implementation of visual and auditory orienting reflexes.

The vestibulo-spinal bundle begins in the nuclei of the vestibular apparatus (in the nucleus of Deiters). The fibers descend into the spinal cord and pass in the anterior and partly lateral columns. The fibers end in the cells of the anterior horns. Since the nucleus of Deiters is connected with the cerebellum, impulses from the vestibular system and the cerebellum to the spinal cord follow this path; participates in the balance function.

The reticular-spinal bundle starts from the reticular formation of the medulla oblongata, passes in different bundles in the anterior and lateral columns of the spinal cord. It ends in the cells of the anterior horn; conducts vital impulses from the coordinating center of the hindbrain.

The posterior longitudinal bundle consists of ascending and descending fibers. It travels through the brainstem to the anterior columns of the spinal cord. Impulses from the brain stem and segments of the spinal cord, from the vestibular apparatus and nuclei of the eye muscles, as well as from the cerebellum pass along this path.

The nerve cell has a large number of processes. The processes removed from the cell body are called nerve fibers. Nerve fibers that do not extend beyond the central nervous system form conductors of the brain and spinal cord. Fibers that travel outside the central nervous system gather into bundles and form peripheral nerves.

Nerve fibers passing inside the brain and spinal cord have different lengths - some of them come into contact with neurons located close, others with neurons located at a greater distance, and still others are far removed from the body of their cell. In this regard, three types of conductors can be distinguished that carry out the transmission of impulses within the central nervous system.

1. Projection conductors communicate with the overlying sections of the central nervous system with the sections located below. Among them, there are two types of paths. Descending conduct impulses from the overlying departments of the go-

TO MOUSE

Rice. 47. Projection fibers of the spinal cord:

1 - posterior spinal bundle; II - fibers of the posterior cord; III - spinal tuberous bundle; IV - anterior cortical-spinal bundle; V - lateral cortical-in-spinal bundle; VI - vestibulo-spinal bundle

Rice. 48. Association Paths:

brain down and are called centrifugal. They are motor in nature. The paths that direct from the periphery the conductive impulses from the skin, muscles, joints, ligaments, bones to the center have an upward direction and are called centripetal. They are sensitive in nature.

Commissural, or adhesive, conductors connect the hemispheres of the brain. Examples of such connections are the corpus callosum, connecting the right and left hemispheres, the anterior commissure, the commissure of the uncinate gyrus, and the gray commissure of the thalamus, connecting both halves of the thalamus.

Associative, or associative, conductors connect parts of the brain within the same hemisphere. Short fibers connect various convolutions in one or closely spaced lobes, and long ones stretch from one lobe of the hemisphere to another. For example, the arcuate bundle connects the lower and middle sections of the frontal lobe, the lower longitudinal connects the temporal lobe with the occipital lobe. Allocate the fronto-occipital, fronto-parietal bundles, etc. (Fig. 48).

Consider the course of the main projection conductors of the brain and spinal cord.

centrifugal ways

pyramid path begins from large and giant pyramidal cells (Betz cells) located in the fifth layer of the anterior central gyrus and paracentral lobule. In the upper sections there are paths for the legs, in the middle sections of the anterior central gyrus - for the trunk, below - for the arms, neck and head. Thus, the projection of human body parts in the brain is presented inverted. A powerful bundle is formed from the total amount of fibers, which passes through the inner bag (in Fig. 36 - see the knee and the front two-thirds of the back of the thigh). Then the pyramidal bundle passes through the base of the brain stem, the pons, entering the medulla oblongata, and then into the spinal cord.

At the level of the pons and medulla, part of the fibers of the pyramidal pathway ends in the nuclei of the cranial nerves (trigeminal, abducens, facial, glossopharyngeal, vagus, accessory, hypoglossal). This short bundle of fibers is called the cortical-bulbar pathway. It starts from the lower sections of the anterior central gyrus. Before entering the nuclei, the nerve fibers of the short pyramidal pathway cross over. Another, longer bundle of pyramidal nerve fibers, starting from the upper sections of the anterior central gyrus, descends down into the spinal cord and is called the cortical-spinal path. The latter, on the border of the medulla oblongata with the spinal cord, forms an incomplete decussation, and most of the nerve fibers (subjected to decussation) continue their way in the lateral columns of the spinal cord, and a smaller part (not crossed) goes as part of the anterior columns of the spinal cord of its side. Both segments end in the motor cells of the anterior horn of the spinal cord.

leg brain and to the nuclei of the cranial nerves, the other - to the muscles of the face, neck, trunk and limbs.

When the pyramidal tract is damaged, movements are disturbed on the side opposite to the lesion, which can be expressed by a complete absence of muscle movements (paralysis) or their partial weakening (paresis). Depending on the location of the lesion, central and peripheral paralysis or paresis are distinguished. The characteristics of these violations are given in the corresponding section.

Monaco beam begins in the midbrain from the red nuclei. Immediately upon exiting the red nucleus, the fibers cross and, having passed the hindbrain, descend into the spinal cord. In the spinal cord, this bundle of nerve fibers is located in the lateral columns near the bundle of the crossed pyramidal pathway and gradually ends, like the pyramidal pathway, in the cells of the anterior horns of the spinal cord.

Monakov's bundle conducts motor impulses that regulate muscle tone.

Roof-spinal bundle connects the anterior colliculus of the midbrain with the anterior and partly lateral columns of the spinal cord. Participates in the implementation of visual and auditory orienting reflexes.

vestibulo-spinal bundle begins in the nuclei of the vestibular apparatus (in the nucleus of Deiters). The fibers descend into the spinal cord and pass in the anterior and partly lateral columns. The fibers end in the cells of the anterior horns. Since the nucleus of Deiters is connected with the cerebellum, impulses from the vestibular system and the cerebellum to the spinal cord follow this path; participates in the balance function.

Retico-spinal bundle starts from the reticular formation of the medulla oblongata, passes in different bundles in the anterior and lateral columns of the spinal cord. It ends in the cells of the anterior horn; conducts vital impulses from the coordinating center of the hindbrain.

Posterior longitudinal beam consists of ascending and descending fibers. It travels through the brainstem to the anterior columns of the spinal cord. Impulses from the brain stem and segments of the spinal cord, from the vestibular apparatus and nuclei of the eye muscles, as well as from the cerebellum pass along this path.

centripetal paths

Pathway of superficial skin sensitivity carries pain, temperature and, in part, tactile sensations (the main path of touch passes with fibers of deep sensitivity). The path begins in the intervertebral node from cells that have two processes, one of them goes to the periphery to the skin receptors, and the other goes to the spinal cord and ends in the cells of the dorsal horn of the spinal cord. This is the so-called first neuron of the sensory pathway. From the cells of the posterior horn, the second neuron of the skin sensitivity pathway begins. It passes to the opposite side and rises along the lateral columns of the spinal cord, passes through the medulla oblongata, and in the pons varolii and in the region of the midbrain it enters into the medial loop and goes to the outer nucleus of the thalamus. From the thalamus begins the third neuron of the sensory pathway; it passes the internal pouch (at the back of the thigh) and travels to the cerebral cortex. It ends in the region of the posterior central gyrus (parietal lobe).

Path of deep sensitivity It also starts from the nerve cells of the intervertebral node, where impulses are suitable not only from the skin and mucous membranes, but also from muscles, joints, bones, tendons and ligaments. The path of deep sensitivity, carrying irritations from all these formations, enters the spinal cord as part of the posterior columns. Then it rises up along the spinal cord to the oblong, in the nuclei of which the first neuron of this path ends. From the nuclei of the medulla oblongata begins the second neuron of deep sensitivity. Upon exiting the nuclei, the fibers cross, then form a medial loop and go to the lateral nucleus of the visual mound. The third neuron of deep sensitivity begins from the visual hillock, it passes through the internal bag and also ends in the cells of the posterior central gyrus (parietal lobe) (Fig. 50).

I- nuclei of the posterior pillars; II - posterior columns of the spinal cord, III - spinal tuberous bundle; IV - trigeminal nerve: P. - median loop: 3. bug. - visual tubercle: M. t. - corpus callosum; Ch. i. - lentil kernel; V. s. - inner bag

cerebellar conductors, like all ascending conductors, they start from the intervertebral node and go to the gray matter of the spinal cord, where they end in the cells of the posterior horn. From the cells of the posterior horn, the second neuron begins, which is sent in two bundles to the lateral columns of the spinal cord. One bundle, straight, reaches the medulla oblongata, forms the lower cerebellar peduncle and ends in the cells of the cerebellum. Another bundle, crossed, rises up to the midbrain and also enters the cerebellum through the superior cerebellar peduncle.

The ascending pathways include sensory pathways that carry olfactory, visual and auditory stimuli. These will be discussed below in the section on cranial nerves.

With the defeat of sensitive conductors, disorders of all types of sensitivity of the corresponding area are observed. So, with the defeat of the corresponding paths of the lateral column, skin (pain and temperature) and partly tactile sensitivity on the opposite side suffers.

In connection with the defeat of the fibers of the cerebellar pathways, disorders of coordination of movements occur. With the defeat of the posterior pillars, deep sensitivity is disturbed - a sense of the position of the organs of movement, localization, a two-dimensional spatial sense. In this regard, the gait is also disturbed, which becomes uncertain, the movements are sweeping, inaccurate.

cranial nerves

The cranial nerves originate in the brainstem, where their nuclei are located. The exceptions are the olfactory, auditory and optic nerves, the first neuron of which is located outside the brain stem.

Most cranial nerves are mixed, i.e. contain both sensory and motor fibers, with sensory predominating in some, and motor in others.

In total there are twelve 12 cranial nerves (Fig. 51).

/ pair - olfactory nerve. It begins in the nasal mucosa in the form of thin nerve threads that pass through ethmoid bone skulls, go to the base of the brain and are collected in the olfactory bulb. From the olfactory bulb comes the secondary olfactory pathway - olfactory tract. The fibers of the olfactory tract partly diverge, forming a triangle. Most of the olfactory fibers end in the central nucleus of the olfactory analyzer, located in the uncinate gyrus on the inner surface of the cortex.

The sense of smell is examined with a set of odorous substances.

The olfactory disorder can be expressed in different ways: in the form total absence perception of odors - anosmia, or a decrease in the perception of odors - hyposmia. Sometimes there is a particularly hypersensitivity to odorous substances - hyperosmia (in childhood almost never seen).

It should be borne in mind that sometimes local damage to the nasal mucosa (for example, with a runny nose) disrupts the perception of odors, which is not at all associated with damage to the olfactory tract itself.

2 pair - optic nerve. The visual path (Fig. 52) begins in the retina. The retina of the eye has a very complex

nerve fibers approaches the nuclei of the anterior tubercles of the quadrigemina, to the pillow of the thalamus.

From the cells of the external geniculate body, the visual path is directed to the cerebral cortex. This segment of the path is called the Graziole bundle.

The visual path ends in the cortex of the occipital lobe, where the central nucleus of the visual analyzer is located.

Visual acuity in children can be checked using a special table. Color perception is checked by a set of color pictures.

structure, it consists of cells called rods and cones. These cells are receptors that perceive various light and color stimuli. In addition to these cells, there are ganglionic nerve cells in the eye, the dendrites of which end in cones and rods, and the axons form the optic nerve. The optic nerves enter the cranial cavity through the bony opening and pass along the bottom of the base of the brain. At the base of the brain, the optic nerves form a half decussation - chiasma. Not all nerve fibers are crossed, but only fibers coming from the inner halves of the retina; the fibers coming from the outer halves do not cross.

massive beam neural pathways, which is formed after the intersection of the optic fibers, is called the optic tract. Thus, in the optic tract of each side, nerve fibers pass not from one eye, but from the same halves of the retinas of both eyes. For example, in the left optic tract from both left halves of the retinas, and in the right - from both right halves (Fig. 52).

Most of the nerve fibers of the optic tract go to the external geniculate bodies, a small part

Visual pathway lesion may occur in Fig. 52. Scheme of the visual pathways

1 - „ (according to Bing)

any segment. IN depending on this, a different clinical picture of visual impairment will be observed.

Basically, it is necessary to distinguish three areas of the lesion: before the chiasm, in the region of the chiasm itself (chiasm) and after the optic chiasm. More on this will be discussed below.

L / (oculomotor nerve), IV (trochlear nerve) and VI (abducens nerve) pairs of nerves carry out the movements of the eyeball and are, therefore, oculomotors. These nerves carry impulses to the muscles that move the eyeball. With the defeat of these nerves, paralysis of the corresponding muscles and restrictions on the movements of the eyeball - strabismus are observed.

In addition, with the defeat of the III pair of cranial nerves, ptosis (drooping of the upper eyelid) and inequality of the pupils are also observed. The latter is also associated with damage to the branch of the sympathetic nerve, which is involved in the innervation of the eye.

V pair - the trigeminal nerve leaves the skull on the front surface, forming three branches: a) orbital, b) zygomatic, c) mandibular.

The first two branches are sensitive. They innervate the skin of the upper facial region, the mucous membranes of the nose, eyelids, as well as the eyeball, upper jaw, gums and teeth. Part of the nerve fibers supplies the meninges.

The third branch of the trigeminal nerve is mixed in terms of fiber composition. Its sensory fibers innervate the lower part of the skin surface of the face, the anterior two-thirds of the tongue, the mucous membrane of the mouth, teeth and gums. mandible. The motor fibers of this branch innervate the masticatory muscles.

The sympathetic nerve plays an important role in the system of innervation of the trigeminal nerve.

With the defeat of the peripheral branches of the trigeminal nerve, the skin sensitivity of the face is upset. Sometimes there are excruciating attacks of pain (trigeminal neuralgia), due to the inflammatory process in the nerve. Disorders of the motor portion of the fibers cause paralysis of the masticatory muscles, as a result of which the movements of the lower jaw are sharply limited, which makes it difficult to chew food.

VII pair - the facial nerve (motor) is suitable for all the facial muscles of the face. With a unilateral lesion of the facial nerve, which often occurs as a result of a cold, nerve paralysis develops, in which the following picture is observed: low position eyebrows, palpebral fissure is wider than on the healthy side, the eyelids do not close tightly, the nasolabial fold is smoothed, the corner of the mouth sags, voluntary movements are difficult, it is not possible to frown and lift them up, evenly inflate the cheeks, it is not possible to whistle with lips or pronounce the sound "y". Patients at the same time feel numbness in the affected half of the face, experience pain. Due to the fact that the composition of the facial nerve includes secretory and taste fibers, salivation is disturbed, taste is upset. The fibers of the trigeminal nerve are also involved in the implementation of the function of taste.

VIII pair - auditory nerve begins in the inner ear with two branches. The first - the auditory nerve itself - departs from the spiral ganglion located in the cochlea of the labyrinth. The cells of the spiral ganglion are bipolar, i.e. have two processes, and one group of processes (peripheral) goes to the hair cells of the organ of Corti, the others form the auditory nerve. The second branch of the mixed auditory nerve is called the vestibular nerve, departing from the vestibular apparatus, also located in the inner ear. It consists of three bony tubules and two sacs. A fluid circulates inside the canals - endolymph, in which calcareous pebbles - otoliths float. The inner surface of the sacs and canals is equipped with sensory nerve endings coming from the Scarpov nerve ganglion, which lies at the bottom of the inner ear canal. The long processes of this node form the vestibular nerve branch. When exiting inner ear auditory and vestibular branches join.

Having entered the cavity of the medulla oblongata, these nerves approach the nuclei lying here, after which they are again disconnected, each following its own direction.

From the nuclei of the medulla oblongata, the auditory nerve goes already under the name of the auditory pathway. Moreover, part of the fibers crosses at the level of the bridge and passes to the other side. The other part goes along its side, including neurons from some nuclear formations (trapezoid body, etc.). This segment of the auditory pathway is called the lateral loop; it ends in the posterior tubercles of the quadrigemina and the internal geniculate bodies. The crossed auditory pathway also fits here. From the internal geniculate bodies, the third segment of the auditory pathway begins, which passes through the internal bag and approaches the temporal lobe, where the central nucleus of the auditory analyzer is located.

With unilateral damage to the auditory nerve and its nuclei, deafness develops in the ear of the same name. With unilateral injury auditory tract(in particular, the lateral loop), as well as the cortical auditory zone, there are no pronounced auditory disorders, there is some hearing loss in the opposite ear (due to double innervation). Complete cortical deafness is possible only with bilateral foci in the corresponding auditory zones.

The vestibular nerve, starting from the Scarp's node and having traveled some distance together with the auditory branch, enters the cavity of the medulla oblongata and approaches the angular nucleus. The angular nucleus consists of the lateral nucleus of Deiters, the superior nucleus of Bekhterev and the inner nucleus. From the angular nucleus, the conductors go to the cerebellar vermis (dentate and roofing nuclei), to the spinal cord along the fibers of the vestibulo-spinal and posterior longitudinal bundle. Through the latter, a connection is made with the oculomotor nuclei of the midbrain. There is a connection with the thalamus.

With the defeat of the vestibular apparatus, as well as the vestibular nerve and its nuclei, the balance is upset, dizziness, nausea, and vomiting appear.

IX pair - glossopharyngeal nerve includes sensory, motor, and secretory fibers. The glossopharyngeal nerve originates from four nuclei located in the medulla oblongata, some nuclei are common with the vagus nerve. This pair of nerves is closely related to the X pair (vagus nerve). The glossopharyngeal nerve supplies sensory (gustatory) fibers to the posterior third of the tongue and palate, and together with the vagus nerve innervates the middle ear and pharynx. The motor fibers of this nerve, together with the branches of the vagus nerve, supply the muscles of the pharynx. Secretory fibers innervate the parotid salivary gland.

With the defeat of the glossopharyngeal nerve, a number of disorders are observed, for example, taste disorders, a decrease in sensitivity in the pharynx, as well as the presence of mild spasms of the pharyngeal muscles. In some cases, salivation may be impaired.

X pair - the vagus nerve departs from the nuclei located in the medulla oblongata, some of the nuclei are common with the IX pair. The vagus nerve performs a number of complex functions of a sensitive, motor and secretory nature. So, it supplies motor and sensory fibers to the muscles of the pharynx (together with the IX pair), soft palate, larynx, epiglottis, vocal cords. Unlike other cranial nerves, this nerve extends far beyond the skull and innervates the trachea, bronchi, lungs, heart, gastrointestinal tract and some other internal organs, as well as blood vessels. Thus, the further course of its fibers takes part in the autonomic innervation, forming the parasympathetic nervous system.

In case of dysfunction vagus nerve, especially with bilateral partial damage, a number of severe disorders can occur, such as swallowing disorders, voice changes (nasality, dysphonia, aphonia); there is a series severe violations from the cardiovascular and respiratory systems. With full you-

If the function of the vagus nerve is turned off, death may occur due to paralysis of the heart and respiratory activity.

XI pair - accessory nerve, is a motor nerve. Its nuclei are located in the spinal cord and medulla oblongata. The fibers of this nerve innervate the muscles of the neck and shoulder girdle, in connection with which such movements as turning the head, raising the shoulders, bringing the shoulder blades to the spine are carried out.

With damage to the accessory nerve, atrophic paralysis of these muscles develops, as a result of which it is difficult to turn the head, the shoulder is lowered. When the nerve is irritated, tonic convulsions of the cervical muscles can occur, as a result of which the head is forcibly tilted to the side (torticollis). Clonic spasm in these muscles (bilateral) causes violent nodding movements.

XII pair - hypoglossal nerve. These are the motor nerves of the tongue. The fibers start from the nucleus located at the bottom of the rhomboid fossa. Fibers of the XII pair innervate the muscles of the tongue, giving it maximum flexibility and mobility. With damage to the hypoglossal nerve, atrophic phenomena can develop in the muscles of the tongue, its ability to move is weakened, which is necessary to perform the speech function and the function of eating. In such cases, speech becomes unclear, it becomes impossible to pronounce complex words. With bilateral damage to the hypoglossal nerve, anarthria develops. A typical picture of speech and phonation disorders is observed with a combined lesion of the IX, X and XII pairs of nerves, known as bulbar palsy. In these cases, the nuclei of the medulla oblongata or the roots and nerves extending from them are affected. There is paralysis of the tongue, severe speech disorders, as well as swallowing disorders, choking, liquid food pours out through the nose, the voice becomes nasal. Such paralysis is accompanied by muscle atrophy and bears all the signs of peripheral paralysis. More often there are cases of lesions of the central pathway (cortical-bulbar). In childhood, with bilateral lesions of the cortical-bulbar tract, for example, after suffering parainfectious encephalitis, phenomena develop that are outwardly similar to bulbar paralysis, but differing in the nature of localization. Since this paralysis is central, there is no muscle atrophy. This type of disorder is known as pseudobulbar palsy.

Spinal cord ( medulla spinalis) - the initial department of the central nervous system. It is located in the spinal canal and is a cylindrical cord flattened from front to back, 40–45 cm long and weighing 34–38 grams. From above, it passes into the medulla oblongata, and from below it ends with a sharpening - a cerebral cone at the level of 1-2 lumbar vertebrae. Here, a thin terminal (terminal) thread departs from it - this is a vestige of the caudal (tail) end of the spinal cord. The diameter of the spinal cord in different parts is different. In the cervical and lumbar regions, it has thickenings (accumulations of gray matter) due to the innervation of the upper and lower extremities. On the anterior surface of the spinal cord there is an anterior median fissure, on the posterior surface - the posterior median sulcus. They divide the spinal cord into right and left halves, which are interconnected. On each half, the anterior lateral and posterior lateral grooves are distinguished. The anterior is the exit point of the anterior motor roots from the spinal cord, the posterior is the entry point of the posterior sensory roots of the spinal nerves. These lateral grooves are the boundary between the anterior, lateral, and posterior cords of the spinal cord. Inside the spinal cord there is a gap filled with cerebrospinal fluid (CSF) - the central canal. From above, it passes into the 4th ventricle, and from below it blindly ends (terminal ventricle). In an adult, it partially or completely overgrows.

Parts of the spinal cord:

cervical

Thoracic

Lumbar

sacral

coccygeal

Each part has segments - a section of the spinal cord corresponding to 2 pairs of roots (2 anterior and 2 posterior).

Throughout the spinal cord, 31 pairs of roots depart. Accordingly, 31 pairs of spinal nerves in the spinal cord are divided into 31 segments:

8 - cervical

12 - chest

5 - lumbar

5 - sacral

1-3 - coccygeal

The lower spinal nerves descend downward to form a ponytail.

As the body grows, the spinal cord does not keep pace with the spinal canal in length, and therefore the nerves are forced to descend, leaving the corresponding openings. Newborns do not have this formation.

Inside the spinal cord is gray and white matter. Gray - neurons that form 3 gray columns in each half of the spinal cord: anterior, posterior and lateral. In cross section, the pillars look like gray horns. There are wide anterior and narrow posterior horns. The lateral horn corresponds to the intermediate vegetative column of gray matter. In the gray matter of the anterior horns, motor neurons pass, in the posterior - sensitive, and in the lateral - intercalary vegetative. Intercalary inhibitory neurons are also located here - Renshaw cells, which inhibit the motor neurons of the anterior horns. The white matter surrounds the gray matter and forms the cords of the spinal cord. There are anterior, posterior and lateral cords in each half of the spinal cord. They consist of longitudinally running nerve fibers, collected in bundles - pathways. The white matter of the anterior cords contains descending pathways (pyramidal and extrapyramidal), in the lateral ones - descending and ascending paths:

anterior and posterior spinocerebellar tracts (Govers and Flexig)

lateral spinothalamic pathway

lateral cortical-spinal tract (pyramidal)

Red nuclear spinal tract

In the white matter of the posterior cords there are ascending pathways:

thin (gentle) Gaulle's bundle

wedge-shaped bundle of Burdach

The connection of the spinal cord with the periphery is carried out with the help of nerve fibers passing in the spinal roots. The anterior roots contain centrifugal motor fibers, the posterior roots contain centripetal sensory fibers. This fact is called the law of distribution of afferent and efferent fibers in the spinal roots - Francois Magendie's law. Therefore, with a bilateral transection of the posterior roots of the spinal cord, the dog loses sensitivity, and the anterior roots lose muscle tone below the site of the transection.

The spinal cord is covered on the outside by 3 meninges:

inner - soft

medium - arachnoid

external - solid

Between the hard shell and the periosteum of the spinal canal is the epidural space filled with fatty tissue and venous plexuses. Between the hard and arachnoid - subdural space, penetrated by thin connective tissue crossbars. The arachnoid membrane is separated from the soft one by the subarachnoid subarachnoid space containing the cerebrospinal fluid. It is formed in the choroid plexuses of the ventricles of the brain (protective and trophic functions). In the spinal cord there are special inhibitory cells - Renshaw cells - that protect the central nervous system from overexcitation.

Functions of the spinal cord.

1. Reflex: carried out by the nerve centers of the spinal cord, which are segmental working centers of unconditioned reflexes. Their neurons communicate with receptors and working organs. Each metamere (transverse section) of the body receives sensitivity from 3 roots. Skeletal muscles also receive innervation from 3 neighboring segments of the spinal cord. Efferent impulses go to the skeletal muscles, respiratory muscles, internal organs, vessels and glands. The overlying parts of the CNS control the periphery with the help of segmental parts of the spinal cord.

2. Conduction: carried out due to the ascending and descending pathways of the spinal cord. Ascending pathways transmit information from tactile, pain, temperature and proprioceptors of muscles and tendons through spinal cord neurons to other parts of the CNS to the cerebellum and cortex big brain.

Pathways of the spinal cord.

Ascending tracts of the spinal cord.

They carry out the transmission of pain, temperature, tactile sensitivity and proprioceptive sensitivity from receptors to the cerebellum and CBM.

1. anterior spinothalamic pathway - afferent pathway of touch and pressure

2. lateral spinothalamic path - path of pain and temperature sensitivity

3. anterior and posterior spinal tracts - Gowers and Flexig paths - afferent paths of musculo-articular sensitivity of the cerebellar direction

4. thin (gentle) Gaulle's bundle and Burdakh's wedge-shaped bundle - afferent pathways of muscle-articular sensitivity of the cortical direction from the lower limbs and lower half of the body and from upper limb and upper body, respectively.

Descending tracts of the spinal cord.

They carry out the transmission of nerve impulses (commands) from the KBM and underlying departments to the working organs. They are divided into pyramidal and extrapyramidal.

Pyramidal pathways of the spinal cord.

They conduct impulses of voluntary motor reactions from the CBM to the anterior horns of the spinal cord (control of conscious movements).

1. anterior cortical - spinal tract

2. lateral corticospinal tract

Extrapyramidal pathways of the spinal cord.

They control involuntary movements. An example of their work is the maintenance of balance by a person in the event of a fall.

1. reticular - spinal path (reticulospinal): from the reticular formation of the brain

2. Tire-spinal tract (tetospinal): from the pons

3. vestibulospinal (vestibulospinal): from the organs of balance

4. red nuclear - spinal (rubrospinal): from the midbrain

Spinal nerves and nerve plexuses.

The human spinal cord has 31 segments, hence 31 pairs of spinal nerves.

8 pairs of neck

12 pairs of chest

5 pairs of lumbar

5 pairs of sacral

1 pair of coccygeal

Formation of the spinal nerve.

Each spinal nerve is formed by connecting the anterior motor and posterior sensory roots. When leaving the intervertebral foramen, the nerve divides into 2 main branches: anterior and posterior. Their functions are mixed. In addition, a meningeal branch departs from the nerve, which returns to spinal canal and innervates hard shell spinal cord and a white connecting branch, suitable for the nodes sympathetic trunk. With various curvature of the spinal column (pathological lordosis, kyphosis and scoliosis), the intervertebral foramens are deformed and pinch the spinal nerves, which leads to dysfunction, neuritis and neuralgia. These nerves supply the spinal cord with:

1. sensitive: torso, limbs, part of the neck

2. motor: all muscles of the trunk, limbs and part of the neck

3. sympathetic: all organs that have it

4. parasympathetic: pelvic organs

The posterior branches of all spinal nerves have a segmental arrangement and pass along the posterior surface of the trunk, where they are divided into skin and muscle branches that innervate the skin and muscles of the occiput, neck, back and pelvis. These branches are named after the corresponding nerves: the posterior branch of the first thoracic nerve, the second, etc. Some have names: the posterior branch of the first cervical nerve - under occipital nerve, the second cervical - a large occipital nerve. All anterior branches of the SMN are thicker than the posterior ones. 12 pairs of thoracic SMNs have a segmental arrangement and run along the lower edges of the ribs - the intercostal nerves. They innervate the skin and muscles of the anterior and lateral walls chest and belly. May become inflamed - intercostal neuralgia. The anterior branches of the remaining SMNs form plexuses (pleksus), the inflammation of which is plexitis.

1. cervical plexus: formed by the anterior branches of the four upper cervical nerves. located in the region of 4 upper cervical vertebrae on the deep muscles of the neck. From the front and side it is covered by the sternocleidomastoid muscle. Sensory, motor and mixed nerves depart from this plexus.

Sensory nerves: small occipital nerve, large ear, transverse nerve of the neck, supraclavicular nerves (innervate the skin of the lateral part of the occiput, auricle, external auditory canal, anterolateral region of the neck, skin in the region of the collarbone and below it)

Muscular branches innervate the deep muscles of the neck, trapezius, sternocleidomastoid and subhyoid muscles

· Mixed branches: phrenic nerve, which is the largest nerve plexus. Its motor fibers innervate the diaphragm, and its sensory fibers innervate the pericardium and pleura.

2. Brachial plexus: formed by the anterior branches of the four lower cervical, part of the anterior branch of the fourth cervical and first thoracic SMN. In the plexus, supraclavicular (short) and subclavian (long) branches are distinguished. Short branches innervate the muscles and skin of the chest, all the muscles of the shoulder girdle and the muscles of the back.

The shortest branch is the axillary nerve, which innervates the deltoid, teres minor, and capsule shoulder joint. Long branches innervate the skin and muscles of the free upper limb.

Medial cutaneous nerve of the shoulder

medial cutaneous nerve of the forearm

Muscular - cutaneous nerve (muscles - shoulder flexors and skin of the anterolateral surface of the forearm)

Median nerve (anterior group of muscles of the forearm, except for the ulnar flexor of the wrist, on the hand, the muscles of the elevation of the thumb, with the exception of the adductor muscle, 2 worm-shaped muscles and the skin of the lateral part of the palm)

· Ulnar nerve(flexor carpi ulnaris, muscles of the little finger eminence, all interosseous, 2 vermiformes, adductor thumb, and skin of the medial hand)

Radial nerve - the largest nerve of this plexus (muscles - extensors of the shoulder and forearm, skin of the back of the shoulder and forearm)

3. Lumbar plexus: formed by the anterior branches of the upper 3 lumbar nerves and partly by the anterior branches of the 12th thoracic and 4th lumbar nerves. Located in the thickness of the lumbar muscle. Short branches of the plexus innervate the square muscle of the lower back, iliac psoas, abdominal muscles and skin of the lower parts of the abdominal wall and external genital organs (muscular branches, ilio-hypogastric and ilio-inguinal and femoral-genital nerves). Long branches innervate the free lower limb.

Lateral cutaneous nerve of thigh

· femoral nerve(anterior thigh muscle group and skin above it). The largest nerve of this plexus. Its large subcutaneous branch is the saphenous nerve (descends along the medial surface of the lower leg of the foot)

The obturator nerve descends into the small pelvis through the obturator canal, exits to the medial surface of the thigh and innervates the medial thigh muscle group, the skin above them and the hip joint

4. sacral plexus: formed by the anterior branches of the 4th - 5th lumbar nerves and the upper 4th sacral. It is located in the pelvic cavity on the anterior surface of the piriformis muscle. Short branches:

upper gluteal

Lower gluteal

sexual

internal obturator

pear-shaped

quadratus femoris nerve

Long branches:

Posterior femoral cutaneous nerve

sciatic nerve

Both nerves exit through the piriformis foramen, where the posterior femoral cutaneous nerve innervates the skin of the perineum, gluteal region and posterior thigh, and the sciatic (the largest in the body) the entire posterior thigh muscle group. It then splits into 2 branches:

1. tibial

2. common peroneal

The tibial nerve behind the lateral malleolus divides into the plantar nerves, and the common peroneal divides into the superficial and deep nerves. They go to the back of the foot. Combining on the posterior surface of the lower leg, both nerves form the sural nerve, which innervates the skin of the lateral edge of the foot.

Neuritis - inflammation of the nerve

Radiculitis - inflammation of the roots of the spinal cord

Plexitis - inflammation of the nerve plexus

Polyneuritis - multiple nerve damage

Neuralgia - soreness along the course of the nerve, not accompanied by dysfunction of the organ

Causalgia - burning pain along the course of the nerve, arising after damage to the nerve trunks

Lumbago - sharp pain that occurs in the lumbar region at the time of physical exertion (weight lifting)

Discogenic radiculopathy - pain motor disorders caused by damage to the roots of the spinal cord due to osteochondrosis of the spine

Myelitis - inflammation of the spinal cord

Epiduritis - purulent inflammation fiber in the epidural space of the spinal cord

Syringomyelia - the formation of cavities in the gray matter of the spinal cord

Poliomyelitis - acute viral disease characterized by damage to the cells of the anterior horns of the spinal cord and the motor nuclei of the cranial nerves.

It is one of the main divisions of the central nervous system. Its development begins almost from the first minutes of the intrauterine formation of the human body. One of the elements of protection of the spinal cord are the membranes of the spinal cord. It is located in the cavity of the spine. Due to the relative strength of the vertebrae, the spinal cord retains its integrity.

What is the spinal cord?

The cord of the spinal cord is a column. It looks like an elongated cylinder with pointed ends. Surprisingly, but important element the human body weighs only up to 40 g. A cord begins at the base of the brain (at the level of the beginning cervical spine), near the occipital foramen. The border between the medulla oblongata and the spinal cord is close to the foramen magnum. It ends approximately at the level of the first or second vertebrae of the lumbar spine. Approaching the end, it begins to narrow, forming a cone, from which a thin thread of the spinal cord descends - the terminal thread. In this thin thread are nerve fibers. The cone of the spinal cord already resembles large cluster connective tissue which has three layers. The terminal thread of the dorsal region, which comes from the cone of the spinal cord, ends just below the second vertebra of the lumbar region. There it converges with the periosteum. In this area, a cauda equina is formed - an accumulation of nerve endings of the spinal cord, braiding a thread with connective tissue.

The spinal cord has several spheres that cover it. The main membranes of the spinal cord:

cobweb;
hard;
soft.

The main canal is first covered with a soft layer, then comes the arachnoid layer of the brain membrane. Its processes pass from the main canal through the soft and hard protective layers of the membrane of the spinal cord and brain. The main functions (nutrition and protection) are performed by the membranes of the spinal cord and brain.

Furrows and thickenings

When viewed from the position of the spine, then the cervical and lumbar mobile, and the thoracic region is fixed. This is due to the fact that the spine in this place with the ribs protects the lungs, heart and other internal organs from damage. It is in the departments that have mobility that there is a high probability of damage.

For this reason, the spinal cord in these departments has seals. These are zones of cervical thickening and lumbosacral compaction. Moreover, there are additional clusters of nerve endings. Their function is the innervation of the upper and lower extremities.

The spinal cord is divided in half by fissures. These are furrows. These furrows are symmetrical (front and back). The anterior and posterior sulci of the spinal cord are the boundaries. For example, in front of it there is a root of movement, and these grooves are separated by front and third-party ropes. Furrows are very important.

Substance, segments and roots

The spinal cord has anterior and posterior roots. These are also nerve endings. The anterior roots arise from the gray matter of the CNS. The posterior roots are sensitive cells that penetrate the nervous system, intertwining, the anterior and posterior endings form nodes.

There are 62 spines in total. They branch out in different directions throughout the size of the spinal cord. It turns out 31 roots on each side. A segment is already a part of the spinal cord, which is located between the paired "forks" - roots. Accordingly, the number of dorsal segments is 31. There are 8 segments in the cervical region, 12 in the thoracic region, 5 segments in the lumbar region, 5 segments in the sacrum, and the last segment in the coccyx. This is somewhat consistent with the number of vertebrae in the human body, but still the spinal cord is shorter than the spine, so some segments do not correspond to their localization when compared with a vertebra.

The spinal nerve cord includes not only process roots. It also has white and gray matter. At the same time, the uniqueness lies in the fact that the white matter comes only from the nerve fibers of the spinal cord, but the gray matter was formed not only by the cells and fibers of the spinal cord, but also by the nerve endings of the brain.

Gray matter

The white matter covers the gray matter. Inside the gray matter is the main canal. In turn, there is cerebrospinal fluid inside the main channel. If we consider the transverse section of the spinal cord, then the white matter has the shape of a butterfly. The transverse section allows you to study in detail the structure of the spinal cord in the transverse direction. The spinal cord (main canal) and the brain (its ventricles, the place between the membranes) are connected not only by nerve endings, but also by the circular movement of cerebrospinal fluid. cerebrospinal fluid regulated by nerve plexuses, which are located in the ventricles of the spinal cord. CSF regulation (its production and reabsorption) occurs in a similar way.

Gray matter is the common name for the columns of the spinal cord. They stick together in one place. This zone is called a plate. This connection gray color. In the center is visible the main canal in which the spinal cord is located. There are two such zones for fastening the pillars: back and front. They are located in the back and front of the main channel. On a transverse section of the spinal cord, such adhesions resemble a butterfly or the letter H in shape.

When examining the spinal cord, one can see how appearances, which are called the horns of the spinal cord, depart from the gray matter. They are located in front and behind. The protrusions located in front are the anterior horns. There are wide paired horns in front, and narrow paired horns behind. The anterior horns contain movement neurons. The anterior roots themselves are formed from neurites. These are the neurons of motion. In the anterior horn there is a nucleus of the spinal cord, and it is not one. The nuclei are formed from the neurons of the horn. In total, there should be five centers-nuclei: central, lateral (2 pcs.), Medial (2 pcs.). From them, the processes are directed to the muscles.

The posterior paired narrow horns have their own nuclei. They are located in the center. Motor nuclei are formed from auxiliary intercalary neurons. Axons are the roots of these nerve cells. They go to the anterior horn, forming ligaments. They intersect with the anterior fastening (commissure) and then pass to the anterior side of the spinal cord. If the intercalary nerve cells reach a large size compared to other neurons, then the dendrites (their endings) branch significantly, forming another nucleus. This nucleus is located near the base of the posterior horn. The nodes of the spinal cord, which are located between the vertebrae, include neuron cells that have significant processes. They reach the centers of the posterior horns.

Between the horns of the anterior and posterior sections of the spinal cord is formed intermediate department. In this zone, the lateral branches (the horns of the spinal cord) diverge from the gray matter. This phenomenon can be seen from the eighth cervical region to the second lumbar segment of the spinal cord.

These branches have a substance that consists exclusively of nerve cells. Their uniqueness lies in the fact that they are calculated exclusively by the autonomic nervous system.

White matter in the brain

The cords of the spinal cord (three pairs: anterior, lateral and posterior) create white matter. The anterior cords are located between the lateral and medial fissures. This is where the front shoots come out. The lateral cords are located between the two lateral fissures. The posterior funiculus can be seen between the lateral and median fissures.

Nerve impulses travel along nerve fibers. These fibers are formed from white matter. Impulses pass in two directions: up (to the brain) and down (in).

The gray matter also has nerve endings that are located between the segments. These short endings connect only closely located neighboring departments. The segmental apparatus of the spinal cord is what they form together. Their purpose is to establish communication between the parts of the spinal cord.

Ganglion neurons form the posterior roots of the spinal cord. Some of them are connected with the posterior horn, and the rest are located on the sides. Another part of the endings goes to the posterior cords. Then they go to the brain. These are the ascending pathways of the spinal organ.

Conduction functions of nerves

The spinal cord performs several very important functions, one of them is a conductor. This means that impulses with information move along the spinal cord to the brain and other organs (and vice versa).

This function is performed by the white matter, the neurons and nerve fibers that make it up. The evolutionary development of the spinal cord has led to the fact that reflex arc constantly becoming more complex as the basis of the nervous system. Development made it possible that where there could previously be only one neuron, knots of nerve fibers began to gradually appear, each of which consisted of an accumulation of nerve cells.

The pathways of the spinal organ are a collection of nerve endings that have general functions and similar structure, development. These fibers connect either the spinal cord and the brain, or different segments of the spinal cord.

All pathways of the spinal cord, depending on their functions, are classified as projection, associative and commissural. Projection pathways can be efferent and afferent. These pathways are the main ones in the central nervous system. They can be ascending and descending. Descending paths are called motor and centrifugal. The ascending paths are called sensitive and centripetal. Ascending fibers use the currents that come from the receptors and are responsible for the factors of the external and internal environment.

The conductive paths of ascent are divided into paths of intero-extero- and proprioceptive sensitivity. There are several main bundles: the path of Gaulle and Burdakh, lateral, dorsal, ventral. Thin and wedge-shaped bundles respond to touch, simple movements, the state of the body in space. The dorsolateral pathway and the thalamic pathway are responsible for temperature and pain control. The Gowers and Flexig bundles are directed to skin receptors and receptors of muscles and ligaments. In addition, they are responsible for the transmission of impulses when pressure is sensed.

The descending fiber conducts electrical currents from the brain to the spinal cord, more precisely, they pass to the nuclei of movement, then the reaction follows.

Operations on the spinal cord

Basically, operations on the brain and spine are open, only in some, extremely rare cases closed interventions can be carried out.

Most common surgical intervention when it is necessary to open the back surface of the spinal cord (this is a laminectomy).

Laminotopias are also often needed - these are operations in which you can expose the spine not in a small segment, but in a large area.

If fixation of the vertebrae is necessary, then various plates and structures are used, but a cut must be made in that place.

When performing operations on the peripheral nervous system, the usual principles are used. A cut is made, a special microscope is used, which allows you to stitch the nerve endings if they have been torn or broken.

Now it is possible to use prostheses for some, not the most significant segments of the spinal cord.

Operations are performed under anesthesia. In some cases, it applies local anesthesia. Depending on the operation, gaseous anesthesia, inhalation, electric anesthesia, etc. can be used.

Recovery after surgery may take different period depending on severity. The following postoperative associated problems may occur:

itching and burning in the incision area for surgery;
headaches and dizziness;
violations in speech, swallowing, seizures, seizures, convulsions.

You need to see a doctor to solve problems. The main ones are listed below.

Symptoms and consequences of atrophy

Spinal cord atrophy is a process in which nerve fibers and cells die, and nerve connections are destroyed. This phenomenon can pass from the spinal cord to the brain.

Statistics show that brain atrophy most often occurs in women after 50 years of age. For several decades, a person can go to dementia. But the disease can also take hold of very young children. The basis of the disease is that the brain mass decreases over time. Scientists believe that the cause is heredity.

Symptoms depend on which spinal region is affected. A person first ceases to be active, becomes lethargic. Sometimes there may be a disregard for moral standards. Then there may be problems with memory, speech, sensory organs, motor skills, over time, the ability to analyze and create one's own opinion is lost.

Despite the development of new treatment methods, the prognosis for patients is not favorable enough. The best solution for treatment will be communication and a good relationship in family. Of the drugs prescribe vitamins and drugs for blood vessels.

We must try to keep active image life, healthy and proper nutrition.

Signs of a meningioma

Meningioma of the brain is a tumor that is located on the spinal canal. It usually arises from the vascular tissues of the layers of the brain. It is most often located almost at the base of the skull. It often doesn't grow at all. long period. Spinal cord meningioma is small and occupies no more than a few vertebrae. But then it can increase in length along the spine. In most cases, meningioma is benign, but it can become malignant or atypical.

It has been established that a tumor can arise and begin to develop from ionizing radiation during pregnancy, and increase during the menstrual cycle.

Radiation treatments or surgery can be used for treatment. Chemotherapy won't positive result if the tumor is benign. The treatment method is chosen depending on the location and size of the tumor. Most often used in the beginning traditional methods to reduce swelling in the area of the neoplasm.

Signs of angioma

Spinal cord angioma is a severe local extension vessels. From the outside, it looks like a red ball of tangled threads. Such an anomaly could arise due to heredity. Angioma can develop at the birth of a person, as well as in old age. The reason for her sudden appearance there may be injuries and infections.

Angioma is manifested by such symptoms as:

headaches and dizziness;
visual impairment, memory, movement coordination;
noises in the head;
convulsions.

Angioma is divided into the following types: venous, capillary, tricky (a tangle of different vessels with thin walls).

If the angioma is small and does not interfere, then it can not be removed. Otherwise, the vessels are specially clogged and removed, so their development will not be observed.

Signs and consequences of a spinal cord rupture

A brain rupture is very difficult to diagnose. The place of the rupture is determined due to the fact that the spinal cord is protected not only by the spine, but also by the muscular base. The occurrence of such a disorder in the functioning of the nervous system as a rupture of the spinal cord can lead to very unpleasant, severe and unpredictable consequences for a person.

Rupture leads to loss of sensation, activity and partial or complete paralysis. The gap can lead to complete or partial disability, which complicates the normal life of a person. Rupture can be caused by car accidents, domestic injuries and falls from high altitude. A person can experience spinal shock when the whole body refuses to work. This often leads to death.

The spinal cord is an important element of the human body. It is better to immediately carry out the prevention of any diseases and, if you are afraid, consult a doctor.

This is done thanks to the synapses, which act as a contactor or disconnector for neurons. Impulses are transmitted only in one direction - from the receptor through the intercalary neuron to the efferent, which is due to the morphofunctional features of the synapses, which conduct only from the presynaptic membrane to the postsynaptic one.

Conducting paths- this is a collection of nerve fibers passing in certain areas of the white matter of the head and, united by a common morphological structure and function.

In the spinal cord and brain, three groups of pathways are distinguished according to their structure and function.

Associative pathways connect areas of gray matter, various functional centers (cerebral cortex, nuclei) within one half of the brain. Allocate short and long associative fibers. Short fibers connect nearby areas of gray matter and are located within one lobe of the brain - intralobar bundles of fibers.

Long associative fibers connect areas of gray matter located at a considerable distance from each other, usually in different zones. These include the upper oblong bundle, connecting the cortex of the frontal lobe with the parietal and occipital, the lower oblong bundle, connecting the gray matter temporal lobe With occipital lobe. Associative fibers connect neurons located in different segments. They form their own bundles (intersegmental bundles), which are located near the gray matter. Short bundles are thrown over 2-3 segments, and long bundles connect distant segments of the spinal cord.

Commissural (commissural (nerve fibers) connect (gray matter) the right and left hemispheres of the brain, form the corpus callosum (commissure), commissure of the arch and anterior commissure, i.e. commissural fibers pass from one hemisphere to another. Fibers are located in the corpus callosum, connecting new, younger parts of the brain.In the white matter of the hemispheres, the fibers of the corpus callosum diverge fan-shaped, forming the radiance of the corpus callosum.

Projection fibers connect the underlying sections with the basal nuclei and the cortex, and, conversely, the cerebral cortex, the basal nuclei with the nuclei of the brain stem and with the spinal cord. With the help of projection nerve fibers reaching the cerebral cortex, the pictures of the outside world are projected onto the cortex, as if on a screen, where the highest analysis of the incoming impulses and their conscious evaluation take place.

Allocate projection ascending and. Ascending (afferent, sensitive) carry impulses coming from, the musculoskeletal system, internal organs and vessels to the brain, to its subcortical and higher centers. According to the nature of the conducted impulses, the ascending projection paths are divided into 3 groups:

1) exteroceptive pathways - impulses come from the sense organs (hearing, taste, smell), skin (pain, temperature, pressure);

2) proprioceptive pathways - impulses come from the organs of movement, carry information about the position of body parts, about the range of motion;

3) interoreceptive pathways - impulses come from internal organs, blood vessels (chemo-, baro-, mechanoreceptors).

exteroceptive pathways. Pathways of pain and temperature sensitivity form the lateral (lateral) spinal-thalamic pathway.

All ascending pathways consist of 3 neurons:

I neurons are located in the sense organs and end in the spinal cord or in the brain stem.

II neurons are located in the nuclei of the spinal cord or brain and end in the nuclei of the hypothalamus. These neurons form centripetal ascending pathways.

III neurons lie in the nuclei of the diencephalon, for skin and musculo-articular sensitivity - in the nuclei of the thalamus, for visual impulses - in geniculate body, for olfactory impulses - in the mastoid bodies. The processes of neurons end on the cells of the corresponding cortical centers (visual, auditory, olfactory and general sensitivity).

The receptors of the first (sensitive) neuron that perceives irritations are located in the skin and on the mucous membrane, and its body lies in the spinal nodes; the central process goes as part of the posterior root to the posterior horn of the spinal cord. The axon of the second neuron, whose body lies in the posterior horn, is sent to opposite side spinal cord. Through its anterior gray commissure, the axon enters the lateral funiculus, where it is included in the lateral spinal-thalamic pathway, which ascends to. The beam is located behind the olive, passes into the tire of the bridge and the tire. Axons end, forming synapses on cells located in the thalamus (III neuron). The axons of the III neuron reach the cortex of the hemisphere, its post-central (IV layer of the cortex), where the cortical end of the general sensitivity is located. Impulses from skin receptors (receptors that perceive the feeling of pressure and touch) go to the cells of the cortex in the postcentral gyrus - the place of general sensitivity.