Peripheral nervous system. cranial nerves. Sensory nerve What are sensory nerves

The nervous system (NS) ensures the vital activity of the body due to the ability to respond to external and internal stimuli. The NS is divided into central and peripheral. Departments of the National Assembly differ in their functions. The functions of the somatic NS can be controlled by consciousness, meanwhile, the functions of the vegetative NS are not controlled by our consciousness - it regulates vital processes in the body. Nerves are made up of parallel nerve fibers. According to their functions, the fibers of the nervous system are divided into motor nerves, sensory and autonomic.

Motor nerves transmit excitation from the central nervous system to the striated muscles. Thanks to them, we can tense our muscles, breathe, etc.

Through sensory nerves, impulses propagate from peripheral receptors to the central nervous system. Thanks to sensitive fibers, we feel pain, cold and heat, determine the mass and shape of objects.

They form the autonomic or autonomic nervous system, which coordinates the activity of smooth muscles, various glands, and the heart. Autonomous NS is divided into two sections: sympathetic and parasympathetic, which regulate the activity of internal organs in different ways. For example, with increased functioning of the parasympathetic nervous system, diarrhea appears. If the sympathetic NS dominates, then reverse processes occur.

Major motor and sensory nerve fibers

Peripheral NS includes cranial and spinal nerves, as well as nerves of the autonomic nervous system.

cranial nerves

Humans have 12 pairs of cranial nerves. They consist of motor or sensory fibers, or they can be mixed, i.e. consist of both. The cranial nerves originate in the brain stem or medulla oblongata and innervate the tissues of the head and neck. Let's call them all:

• Olfactory (from Latin n. olfactorius).
• Visual (n. opticus).
• Oculomotor (n. oculomotorius).
• Block (n. trochlearis).
• Trinity (n. trigeminus).
• Facial (n. facialis).
• Vestibulocochlearis (n. vestibulocochlearis).
• Removing (n. abducens).
• Glossopharyngeus (n. glossopharyngeus).
• Wandering (n. vagus).
• Additional (n. accesorius).
• Sublingual (n. hypoglossus).

spinal nerves

31 pairs of spinal nerves leave the spinal cord:

• Cervical (8 pairs) - roots extend from the cervical part of the spinal cord.
• Thoracic (12 pairs) - from the thoracic part of the spinal cord.
• Lumbar (5 pairs) - from the lumbar part of the spinal cord.
• Sacral (5 pairs) - from the sacral part.
• Coccygeal (1 pair) - from the end part.

The spinal nerves innervate the muscles of the trunk, as well as the muscles of the lower and upper extremities.

The nervous system regulates and coordinates the activity of all organs. It also ensures the interaction of the body with environment. The nervous system includes the brain and spinal cord (central nervous system), which process information and form commands to change the activity of organs, as well as nerves (peripheral nervous system), which connect the brain with organs.

What are nerves?

Nerves are bundles of fibers (outgrowths of nerve cells) surrounded by special sheaths. The number of nerve fibers in one nerve reaches tens and hundreds of thousands, so the diameter of the nerve ranges from fractions of a millimeter to a centimeter. The length of the nerves and the number of their branches are determined by the peculiarities of the structure and development of the organs to which the nerves are directed.

31 pairs of spinal nerves depart from the spinal cord (to the right and left sides of the body), which serve the organs, muscles and skin of the trunk and limbs. 12 pairs of cranial nerves depart from the brain, regulating the activity of mainly the organs of the head and neck. The longest of all cranial nerves - the vagus - is involved in the regulation of the work of the organs of the chest and abdominal cavities. The cranial nerves have serial numbers and their own names. They depart mainly from the brain stem - there are nuclei (nerve centers) of the cranial nerves. There are sensory, motor and mixed cranial nerves.

Sensory cranial nerves

Sensory nerves transmit information from the sense organs to the brain. These include the olfactory, optic, and vestibulocochlear nerves.

Olfactory nerve
Olfactory nerves transmit information to the brain from receptor cells located in the nasal mucosa. Thin threads of the nerve (15-20) penetrate the cranial cavity, olfactory bulbs lying on the lower surface frontal lobes hemispheres of the brain. From here, the olfactory tracts begin, along which information is sent to the subcortical centers and to the cerebral cortex. If the frontal region is damaged, olfactory disorders are possible.

optic nerve
The optic nerve is formed by processes of nerve cells in the retina of the eye, emerging near the posterior pole of the eyeball. Inside the skull, the optic nerve fibers cross and pass into the optic tract, which ends in the subcortical centers. Further, the pathways go to the highest center in the cortex of the occipital lobe of the hemispheres. At the intersection of the optic nerves, only the nerve fibers coming from the inner halves of the retina cross, creating conditions for binocular vision (obtaining one image in both eyes). With damage to the optic nerve, optic chiasm or optic tract, visual impairment will vary, which makes it possible to diagnose their localization.

Vestibulocochlear nerve
The vestibulocochlear nerve consists of 2 parts: cochlear and vestibular. The first conducts impulses from the organ of hearing, the second - from the organ of balance. Hearing and balance receptors are located inside the temporal bone. Both parts of the nerve are connected in the internal auditory canal, from there they enter the cranial cavity. In the brain, the pathways for conducting auditory and vestibular information are different: the auditory center is located in the temporal lobe of the cerebral hemispheres, and the vestibular center is located in the cerebellum. If the temporal bone is damaged, not only hearing loss and balance disorder are possible, but also a violation of salivation and facial expressions, since next to the vestibulocochlear nerve in the internal auditory canal there is a nerve (facial) involved in the innervation of the salivary glands and facial muscles.

Motor cranial nerves

Motor cranial nerves conduct commands to the muscles of the eyeball, tongue, and some muscles of the neck.

Oculomotor, trochlear and abducens nerves
The oculomotor, trochlear and abducens nerves penetrate from the cranial cavity into the orbit and provide all the variety of movements of the eyeballs and the muscle that lifts the upper eyelid. With damage to the oculomotor nerve, divergent strabismus, eyelid drooping and pupil dilation are observed. Damage to the trochlear nerve gives the slanted position of the eyeballs and causes a doubling of the objects being viewed. If the abducens nerve is damaged, internal strabismus develops.

Accessory and hypoglossal nerves
The accessory nerve goes to the muscles involved in the movements of the head and neck. When it is damaged, torticollis is observed - a tilt of the head with a turn to the other side. The hypoglossal nerve conducts commands to the muscles of the tongue. With its defeat, there is a deviation of the tongue to the affected side, which affects the position of the larynx.

Mixed cranial nerves

The mixed cranial nerves include the trigeminal, facial, glossopharyngeal, and vagus nerves.

Trigeminal nerve
The trigeminal nerve has three main branches: the ophthalmic, maxillary, and mandibular nerves.
The optic nerve passes into the orbit and innervates its contents, the upper eyelid, the skin of the forehead and crown, the mucous membrane of the upper part of the nasal cavity and paranasal sinuses. The maxillary nerve is sensitive to the gums and teeth of the upper jaw, the mucous membrane of the palate, the nasal cavity and the maxillary (maxillary) sinus, the skin of the nose and cheeks. Sensitive fibers of the mandibular nerve are sent to the gums and teeth of the lower jaw, the mucous membrane of the tongue and cheeks, as well as to the skin of the chin and the lower part of the auricle. The motor branches of the mandibular nerve conduct commands to the masticatory muscles. If the trigeminal nerve is damaged, there are violations of the sensitivity of the skin of the face and palate, paralysis of the masticatory muscles may develop.

facial nerve
The facial nerve got its name due to the fact that its motor branches regulate the work of facial muscles. Sensory fibers of the facial nerve conduct taste stimuli from the anterior 2/3 of the tongue. Commands transmitted along the fibers of the facial nerve increase salivation and the production of tear fluid.

Glossopharyngeal nerve
The glossopharyngeal nerve innervates the mucous membrane of the posterior 1/3 of the tongue, the upper part of the pharynx and the tympanic cavity. The nerve contains a branch that conducts information from the carotid arteries to the brain about the state of blood pressure and chemical composition blood. Branches of the glossopharyngeal nerve leading to the muscles of the pharynx and the parotid salivary gland cause increased salivation.

Nervus vagus
The vagus nerve is the longest of the cranial nerves. Its numerous branches go to the muscles of the pharynx and soft palate, the organs of the neck, the skin of the auricle, the heart, the organs of respiration, digestion, the kidneys, and the endocrine glands. The large length of the vagus nerve is explained by the fact that in the distant ancestors of man, the organs innervated by it lay near the head and only in the process of evolution gradually moved back, stretching the nerve fibers.

On the neck, the vagus nerve passes in the region of the carotid artery and internal jugular vein, then goes to the mucous membrane of the root of the tongue, larynx, pharynx and esophagus. Its motor fibers regulate the volume and pitch of the voice and the act of swallowing. A large number of branches of the vagus nerve depart to the heart. In the chest cavity, it passes along the wall of the esophagus and gives branches to the esophagus, trachea, bronchi, lungs and heart, forming nerve plexuses around these organs. Under the influence of the vagus nerve, the heart slows down and weakens contractions, and the bronchi narrow.

Together with the esophagus, the vagus nerve passes through the diaphragm into the abdominal cavity, where it innervates the stomach, liver, spleen, pancreas, kidneys, small intestine and part of the large intestine. Under the action of the vagus nerve, the secretion of the digestive glands and intestinal motility are activated; the adrenal glands reduce the production of hormones. The vagus nerve is involved in the implementation of vomiting. Damage to the vagus nerve, depending on the location, can lead to dysfunction gastrointestinal tract(spastic conditions), disorders of cardiac activity, larynx function (loss of sonority of the voice) and the act of breathing.

Vagotomy
Vagotomy reduces the acidity of gastric juice, because it blocks conduction
to the gastric mucosa of nerve impulses that increase secretion
acids by the parietal cells of the mucosa. When stem
vagotomies cross the entire vagus nerve. With selective
vagotomies cross only certain branches of the nerve.

Nerves entering and leaving the brain are defined in medicine as cranial or cranial nerves (12 pairs). They innervate the glands, muscles, skin and other organs located in the neck, as well as in the abdominal and chest cavities.

Let's talk today about these couples and the violations that occur in them.

Types of cranial nerves

Each of the mentioned pairs of nerves is designated by a Roman numeral from one to twelve, according to their location on the base of the brain. They are in the following order:

1) olfactory;

2) visual;

3) oculomotor;

4) block;

5) trigeminal;

6) outlet;

7) facial;

8) auditory;

9) glossopharyngeal;

10) wandering;

11) additional;

12) sublingual.

They include autonomic, efferent and afferent fibers, and their nuclei are located in the gray matter of the brain. Depending on the composition, all cranial nerves (12 pairs) are divided into sensory, motor and mixed. Let's consider them in this aspect.

sensitive species

This group includes the olfactory, optic and auditory nerves.

Olfactory nerves have processes located in the nasal mucosa. Starting in the nasal cavity, they cross the cribriform plate and approach the olfactory bulb, where the first neuron ends and the central pathway begins.

The visual pair consists of fibers extending from the retina, cones and rods. All nerves enter one trunk in the cranial cavity. First, they form a decussation, and then the optic tract, enveloping the brain stem and giving fibers to the visual centers. One nerve includes about a million fibers (axons of retinal neurons) and, in addition, it has one sheath on the outside and the other on the inside. The nerve enters the skull through the optic canal.

The eighth pair includes auditory cranial nerves - 12 pairs of the rest, except for these three, are motor or mixed. In the auditory nerves, the fibers are directed from the middle ear to the nuclei. Each of them includes the vestibular and cochlear root. They depart from the middle ear and enter the cerebellopontine angle.

Motor types

Another group of 12 pairs of cranial nerves includes the oculomotor, trochlear, accessory, hypoglossal, and abducens nerves.

The third pair, that is, the oculomotor nerves, contain autonomic, motor and parasympathetic fibers. They are divided into upper and lower branches. Moreover, only the upper branches belong to the motor group. They enter the muscle that lifts the eyelid.

The next group includes those that set the eyes in motion. If we compare all the cranial nerves - 12 pairs - then these are the thinnest. They originate from the nucleus on the tegmentum of the midbrain, then go around the leg of the brain and go to the orbit, innervating the superior oblique muscle of the apple of the eye.

They are related to the rectus eye muscle. They have a motor nucleus in the fossa. Leaving the brain, they go to the superior orbital fissure, innervating the rectus eye muscle there.

Accessory nerves originate from the medulla oblongata and cervical regions of the spinal cord. Separate roots are connected into one trunk, passing through the hole and dividing into external and internal branches. The internal branch, in which there are fibers involved in and pharynx, is attached to the vagus nerve.

And the last of the 12 pairs of cranial nerves (a table of which, for convenience, is presented at the end of the article), related to motor, are the origin of this nerve is spinal. But, over time, its spine moved into the skull. It is clear that this is the motor nerve of the tongue. The roots leave the medulla oblongata, then cross the carotid artery and enter the lingual muscles, dividing into branches.

mixed species

This group includes trigeminal, facial, glossopharyngeal and vagus nerves. The mixed nerves have ganglia similar to those of the spinal nerves, but they lack anterior and posterior roots. They have fibers of the motor and sensory types connected into a common trunk. They can also just be around.

The output of 12 pairs of cranial nerves is different. So, the third, seventh, ninth and tenth pairs have parasympathetic fibers in the output areas, which are directed to the autonomic ganglia. Many of them are united by branches where different fibers pass.

The trigeminal nerve has two roots, where the larger one is sensitive, and the smaller one is motor. The innervation of the skin occurs on the parietal, ear and chin areas. The innervation also captures the conjunctiva and the apple of the eye, the hard shell of the brain, the mucous membrane of the mouth and nose, teeth and gums, and also the main part of the tongue.

The trigeminal nerves emerge between the cerebellar peduncle, medially, and the pons. The fibers of the sensitive root belong to the ganglion, which lies in the temporal pyramid near the apex, which was formed as a result of splitting of the hard shell of the brain. They end in the nucleus of this nerve, which is located in the fossa, as well as the nucleus of the spinal tract, continuing into the medulla oblongata, and then heading to the spinal cord. The fibers of the motor nerve root originate from the trigeminal nucleus, which is located in the bridge.

The maxillary, mandibular and ophthalmic nerves depart from the ganglion. The latter is sensitive, divided into nasociliary, frontal and lacrimal. The innervation of 12 pairs of cranial nerves differs not only in the pairs themselves, but also in the derivative branches. Thus, the lacrimal nerve innervates the lateral ophthalmic angle, passing secretory branches to the lacrimal gland. The frontal nerve, accordingly, branches on the forehead and supplies its mucous membrane. The nasociliary innervates the eyeball, and the ethmoid nerves that innervate the nasal mucosa depart from it.

The maxillary nerve is also sensitive, passing into the pterygopalatine fossa and exiting to the anterior facial surface. From it originate the upper alveolar nerves, which pass to the teeth of the upper jaw and gums. The nerve on the cheekbones runs from the ganglion along the posterior nerves of the nose to its mucosa and nasopharynx. The nerve fibers here are sympathetic and parasympathetic.

The mandibular nerve belongs to the mixed type. It consists of a motor root. Its sensory branches include the buccal nerve, which supplies the corresponding mucosa, the ear-temporal nerve, which innervates the skin at the temples and ears, and the lingual, which supplies the tip and back of the tongue. The inferior alveolar nerve is mixed. Passing in the lower jaw, it ends on the chin, branching here in the skin and mucous lower lip. His branches are connected with the autonomic ganglia:

• ear-temporal nerve - with the ear, which innervates the parotid gland;
• lingual nerve - with ganglion, giving innervation to the sublingual and submandibular glands.

The facial nerves include motor and sensory cranial nerves. Mixed fibers create a taste sensation. Some fibers here innervate the lacrimal and salivary glands, while others innervate the anterior two-thirds of the tongue.

The facial nerve consists of motor fibers originating in the superior part of the fossa. It includes the intermediate nerve with taste and parasympathetic fibers. Some are processes of the ganglion, ending with the taste fibers of the vagus and glossopharyngeal nerves. And others begin in the salivary and lacrimal nuclei located next to the motor nucleus.

The facial nerve starts in the brain and then passes into the facial canal through the ear canal. Here is the drum string and, passing through the cavity, connects to the lingual nerve. It includes taste and parasympathetic fibers that reach the submandibular ganglion.

The facial nerve emerges from the bone of the temples and passes into the parotid gland, intertwining there. From here, the branches diverge in a fan-shaped fashion. At this time, all the muscles related to mimic and some others are innervated. A branch on the neck from the facial nerve branches on it in the subcutaneous muscle.

The glossopharyngeal pair realizes the innervation of the lacrimal glands, the posterior part of the tongue, the inner ear and the pharynx. The motor fibers are directed to the stylopharyngeal muscle and constrictors of the pharynx, and the sensory fibers are directed to the parotid gland to the ear ganglion. The nuclei of these nerves, in contrast to where the other nuclei of 12 pairs of cranial nerves are located, are located in the fossa - the triangle of the vagus nerve.

Parasympathetic fibers originate in the salivary nucleus. Glossopharyngeal nerve, moving away from the medulla oblongata, stretches to the base of the tongue. From the ganglion, the tympanic nerve begins, which has parasympathetic fibers that continue to the ear ganglion. Next, the lingual, amygdala and pharyngeal nerves begin. The lingual nerves innervate the root of the tongue.

The wandering pair implements parasympathetic innervation in abdominal cavity as well as in the chest and neck area. This nerve includes motor and sensory fibers. Here is the greatest innervation. The vagus nerve has a double nucleus:

• dorsal;
• solitary path.

Coming out behind the olive on the neck, it moves with the neurovascular bundle, and then branches.

Violations

Functional disorders can have all cranial nerves - 12 pairs. The anatomy of the lesions is manifested at different levels of nuclei or trunks. To make a diagnosis, an in-depth analysis of intracranial pathological processes is carried out. If the lesion affects one side of the nuclei and fibers, then most likely it is a violation of the functions of any of the affected 12 pairs of cranial nerves.

Neurology studies, however, the symptoms on the opposite side. Then the lesion of the conductive pathways is diagnosed. It also happens that dysfunctions of the nerves are associated with a tumor, an arachnoid cyst, an abscess, vascular malformations, and other similar processes.

The simultaneous defeat of the 12th pair of cranial nerves, that is, the hypoglossal, as well as the vagus and glossopharyngeal, is called bulbar palsy. This is a very dangerous disease, since there is a possibility of pathology of the most important centers of the brain stem.

Knowledge of the topographic location of the cranial nerves allows you to correctly identify the narrow area of ​​the lesion of each of them. To conduct research, use special techniques. With the appropriate equipment, today it is possible to reveal all the details of the condition of the fundus, the optic nerve, to diagnose the field of view and foci of prolapse. Computerized research allows highly accurate localization of the affected area.

Ophthalmic examination

This technique allows to reveal disturbances in the work of oculomotor, trochlear and efferent pairs of nerves, to identify limited motor activity eyeballs, the degree of exophthalmos and more. The pathology of the optic and auditory nerves can be caused by a narrowing of the canal in the bone or, conversely, by its expansion. Diagnosis is made of the upper slit of the orbit, as well as various openings of the skull.

Verterbal and carotid angiography

This method is important in the recognition of vascular malformations and intracranial processes. However, computed tomography will provide more detailed information on these issues. It visualizes the cranial nerve trunks, diagnoses a tumor of the visual and auditory pair, and other pathologies.

Electromyography

Deepening the study of cranial nerves became possible due to the development of this method. It determines the state of spontaneous muscular chewing and mimic activity, muscles of the tongue, soft palate and other muscles. Also, electromyography allows you to calculate the speed of the impulse along the trunks of the facial, accessory and hypoglossal nerves. To do this, the reflex blinking response is examined, which is provided by the trigeminal and facial nerves.

Neurological examination and symptoms of disorders of individual cranial nerves

This technique is carried out in a certain order. The examination begins with the olfactory nerve. The cotton wool soaked in the irritant is brought to the nostrils in turn. are examined on an ophthalmological examination, on the basis of which, in addition to a direct lesion, even secondary changes can be detected. Pathology can be congestive, dystrophic, inflammatory, or the nerve can be completely destroyed.

Damage to the next three of the 12 pairs of cranial nerves (oculomotor, abducens, and trochlear) causes diplopia and strabismus. There may also be drooping of the upper eyelid, pupil dilation, double vision.

Violations in the fifth pair, that is, in the trigeminal nerves, lead to a deterioration in sensitivity in that part of the face where they are present. This can be observed both in the temples, forehead, and cheekbones, eyes, chin and lips. Sometimes it feels strong pain, rashes and other reactions appear. Due to the fact that the facial nerves have many connections, this pair is characterized by a wide variety of pathological reactions.

In case of violation of the auditory nerve, hearing worsens, the glossopharyngeal - the sensitivity in the inner ear is disturbed, the hypoglossal - the movement of the tongue is limited. In the case of the vagus nerve, paralysis of the soft palate or vocal cord develops. In addition, the rhythm of the heart, respiration, and other visceral-vegetative functions may be disturbed.

Complex disorders and cranial nerves (12 pairs): anatomy, table

The functions of nerve fibers can be impaired both in isolation and in combination, along with various pathologies of the lower skull. So, if all the nerves on one half of the cranial base are affected, then they talk about Garcin's syndrome. With a tumor of the orbital bones and soft tissues, there is a syndrome of the superior orbital fissure. With the defeat of both the olfactory and optic nerves, Kennedy syndrome occurs.

These and other diseases occur both in adults and in childhood. For children, nerve lesions are especially common, which are associated with a malformation.

Below is a structure that can better understand how the cranial nerves work (12 pairs). Anatomy (the table is based on her knowledge) will help you navigate the intricacies of the functioning of their different groups.

Conclusion

We examined all cranial nerves - 12 pairs. Anatomy, table, functions given in the article demonstrate that all cranial nerves have a complex structure, closely related to each other. And if any function is implemented with a restriction or is not performed at all, then there are violations.

Well helps to master all the cranial nerves (12 pairs) table. Neurology, using these data, as well as thanks to special modern equipment, has made significant progress in the possibilities of timely diagnosis and effective treatment patients.

There are twelve pairs of cranial nerves. They are divided into three groups: sensory, motor and mixed.

Sensory nerves include: I pair - olfactory nerve, II pair - optic nerve, VIII pair - vestibulocochlear nerve.

Motor nerves include: IV pair - trochlear nerve, VI pair - abducens nerve, XI pair - accessory nerve, XII pair - hypoglossal nerve.

The mixed nerves include: III pair - oculomotor nerve, V pair - trigeminal nerve, VII pair - facial nerve, IX pair - lingo-pharyngeal nerve, X pair - vagus nerve.

The olfactory nerve (n. Olfactorius) lies at the base of the brain in the frontal lobe (71), consists of the olfactory bulb, the olfactory pathway, which passes into the olfactory triangle, bordering the anterior loose substance. 15-25 thin stovburtsiv depart from the cells of the olfactory bulb, then they pass through the holes in the ethmoid plate of the ethmoid bone to the mucous membrane of the nasal cavity. The olfactory nerve conducts irritation from the olfactory receptors from the nasal cavity to the brain: first, into the papillary-uncinate body of the diencephalon, and then along the arch into the hook of the twist of the marine the ridge, which contains the cerebral end of the olfactory analyzer. This is where olfactory sensations arise.

The optic nerve (n. Opticus) starts from specific cells of the retina, passes through the optic canal, underlies the small wings of the sphenoid bone, in front of the Turkish saddle with the nerve of the second hemisphere of the same name forms an optic junction (chiasm) and continues into the visual path. Its fibers go to the thalamus, where the third neuron of the visual pathway begins, connecting the thalamus with the center of vision, located in the spur groove of the occipital lobe of the cerebral cortex (see 71).

Some fibers of the optic nerve are also connected by the lateral geniculate bodies with the superior tubercles of the tegmentum of the midbrain. This connection makes it possible to direct the eyes to the object that is being examined, and the connection of the optic nerves with the tegmentum-spinal cord in the leading way - to regulate movement in response to the information received.

The oculomotor nerve (n. Oculomotorius) exits the midbrain through the superior orbital fissure of the skull, enters the cavity of the orbit, innervates the superior, inferior, and medial rectus muscles of the eye; fiber), which is included in the military

ny knot and contributes to the narrowing of the muscle, constricts the pupil, and contraction of the muscles of the ciliary body of the eyeball.

The trochlear nerve (n. Trochlearis) exits the skull through the superior orbital fissure, enters the cavity of the orbit, innervates the superior oblique muscle of the eyeball. Its nucleus, like that of the oculomotor nerve, is contained in the midbrain.

The trigeminal nerve (n. Trigeminus) leaves the substance of the brain with two roots: a large one - sensitive and less - mobile. The sensitive root in the cranial cavity forms a trigeminal ganglion, from which three large branches depart: the ophthalmic, maxillary and mandibular nerves (72).

The ophthalmic nerve enters the orbit through the superior orbital fissure and innervates the eyeball, upper eyelid, forehead skin, nasal mucosa, and nasal bridge (73).

The maxillary nerve exits the cranial cavity through a round opening of the large wing of the sphenoid bone, enters the pterygopalatine fossa and gives branches to the teeth of the upper jaw. In addition, this nerve innervates the skin of the lower eyelid, nose, upper lip, part of the nasal mucosa, part of the cheek skin and oral mucosa.

The mandibular nerve exits the cranial cavity through the foramen ovale of the skull along with the motor nerve. The motor branches of this nerve innervate all the masticatory muscles, partially the Digastric muscle. Its sensitive branches innervate the skin of the external auditory canal and temporal region, the buccal mucosa, submandibular and sublingual salivary glands , teeth of the lower jaw, anterior-lower part of the skin of the face, mucous membrane of the back of the tongue. The largest sensitive branches of the mandibular nerve are the lingual, inferior alveolar and ear-temporal.

WITH trigeminal nerve closely related vegetative nodes: ciliary, pterygopalatine, ear and submandibular. Each of

they receive sympathetic and parasympathetic fibers from the trigeminal nerve. Thus, parasympathetic fibers (drum string) pass through the lingual nerve, which carry out the secretory function of the submandibular and sublingual salivary glands.

The abducens nerve (n. Abducens) exits the cranial cavity through the superior orbital fissure and innervates the lateral rectus muscle of the eyeball. The nucleus of this nerve is contained at the bottom of the rhomboid fossa in the region of the bridge.

The facial nerve (n. Facialis) and the intermediate nerve enter the internal auditory opening of the temporal bone, and exit through the styloscopic opening and enter the thickness of the parotid gland. The facial nerve branches into terminal branches that innervate all the facial muscles and the subcutaneous muscle of the neck. the nerve on the face is called the greater crow's foot. In addition, the facial nerve gives off branches to the stylopidiasis muscle and to the posterior abdomen of the digastric muscle. The facial nerve also contains parasympathetic fibers for the lacrimal gland, submandibular and sublingual salivary glands.

The intermediate nerve is a mixed nerve, it is secretory fibers that innervate the lacrimal gland through the pterygopalatine ganglion (large stony nerve), submandibular and sublingual salivary glands (tympanic string). Through the submandibular and sublingual nodes, the fibers of the drum string also innervate the taste buds of the anterior two-thirds of the tongue.

The vestibulocochlearis nerve (n. Vestibulocochlearis) is the nerve of hearing and balance. It exits the cranial cavity through the internal auditory opening just below the facial nerve, passes into the internal auditory canal, where it is divided into two parts: vestibular and curls. The vestibular part innervates a semicircle canals and vestibule. Both nerve processes depart from the synovial node and conduct impulses of a statokinetic nature, which enable a person to navigate in space.

The cochlear part of this nerve has a spiral ganglion, consisting of nerve cells, the peripheral processes of which approach the spiral helix, and the central processes form the helical part of the vestibulocochlear nerve.

The tongue-pharyngeal nerve (n. Glossopharyngeus) exits the cranial cavity through the jugular foramen, passes forward and downward, branches in the pharynx, in the thickness of the root of the tongue, palatine tonsils and arches. It innervates the muscles and mucous membrane of the pharynx, papillae of the tongue, surrounded by a roller, and fibers - the parotid salivary gland. The nuclei of this nerve are located in the medulla oblongata.

The vagus nerve (n. Vagus) exits the cranial cavity through the jugular foramen; it includes motor, sensory and secretory fibers. The vagus nerve passes through the neck as part of the neurovascular bundle, gives branches to the pharynx, larynx, and heart. penetrates in front of the subclavian artery, where it gives off branches to the trachea, bronchi, esophagus and heart bag. In the region of the esophagus, together with the branches of the sympathetic nerve, the branches of the vagus nerve form the anterior and posterior plexuses of the esophagus.