V-IX pairs of cranial nerves. VII pair of cranial nerves - facial nerve Central paresis 7 12 pairs
The first two nerves have significant differences from the rest of the 10 topics, since in fact they are an extension of the brain, formed by protrusion brain vesicles... In addition, they do not have the nodes (cores) that the other 10s have. The nuclei of the cranial nerves, like other ganglia of the central nervous system, are clusters of neurons that perform specific functions.
10 pairs, with the exception of the first two, are not formed from two types of roots (anterior and posterior), as is the case with the spinal roots, but represent only one root - anterior (in III, IV, VI, XI, XII) or posterior (in V, from VII to X).
A common term for this type of nerve is cranial nerves, although Russian-language sources prefer to use cranial nerves. This is not a mistake, but it is preferable to use the first term - in accordance with the international anatomical classification.
All cranial nerves are laid in the embryo already in the second month. At the 4th month of prenatal development, myelination of the vestibular nerve begins - the myelin is imposed on the fibers. Motor fibers go through this stage earlier than sensitive ones. The state of the nerves in the postnatal period is characterized by the fact that, as a result, the first two pairs are the most developed, the rest continue to become more complex. The final myelination occurs by about one and a half years of age.
Classification
Before proceeding with a detailed examination of each individual pair (anatomy and function), it is best to familiarize yourself with them using brief characteristics.
Table 1: Characteristics of 12 pairs
| Numbering | Name | Functions |
|---|---|---|
| I | Olfactory | Susceptibility to odors |
| II | Visual | Transmission of visual stimuli to the brain |
| III | Oculomotor | Eye movements, pupillary response to light exposure |
| IV | Block | Moving the eyes downward, outward |
| V | Trigeminal | Facial, oral, pharyngeal sensitivity; the activity of the muscles responsible for the act of chewing |
| VI | Diverting | Outside eye movement |
| Vii | Facial | Muscle movement (mimic, stirrup); activity salivary gland, anterior tongue sensitivity |
| VIII | Auditory | Transmission of sound signals and impulses from the inner ear |
| IX | Glossopharyngeal | Throat levator movement; activity of the paired salivary glands, sensitivity of the throat, middle ear cavity and auditory tube |
| X | Wandering | Motor processes in the muscles of the throat and some parts of the esophagus; providing sensitivity in the lower throat, partly in the ear canal and eardrums, the dura mater of the brain; activity of smooth muscles (gastrointestinal tract, lungs) and cardiac |
| XI | Additional | Abduction of the head in various directions, shrugging of the shoulders and adduction of the shoulder blades to the spine |
| XII | Sublingual | Moving and moving the tongue, swallowing and chewing |
Nerves with sensory fibers
The olfactory begins in the nerve cells of the nasal mucous membranes, then passes through the ethmoid plate into the cranial cavity to the olfactory bulb and rushes into the olfactory tract, which, in turn, forms a triangle. At the level of this triangle and tract, in the olfactory tubercle, the nerve ends.
The retinal ganglion cells give rise to the optic nerve. Having entered the cranial cavity, it forms a cross and in the further passage begins to be called the "optic tract", which ends in the lateral geniculate body. From it originates the central part of the visual pathway, going to the occipital lobe.
Auditory (aka vestibule-cochlear) consists of two. The cochlear root, formed from the cells of the spiral node (belonging to the cochlear plate), is responsible for the transmission of auditory impulses. The vestibular ganglion, which runs from the vestibular ganglion, carries the impulses of the vestibular labyrinth. Both roots articulate into one in the internal auditory canal and are directed inward in the middle of the pons varoli and the medulla oblongata (VII pair is located slightly below). The fibers of the vestibular section - a significant part of them - pass into the posterior longitudinal and vestibulospinal bundles, the cerebellum. Cochlear fibers stretch to the lower tubercles of the quadruple and the middle geniculate body. Here the central auditory path begins, ending in the temporal gyrus.
There is one more sensory nerve that has received number zero. At first, it was called "additional olfactory", but was later renamed terminal due to the location of the terminal plate nearby. Scientists have yet to establish reliably the functions of this pair.
Motor
The oculomotor, starting in the nuclei of the midbrain (below the aqueduct), appears on the cerebral base in the region of the leg. Before heading to the orbit, it forms a branched system. Its upper section is made up of two branches going to the muscles - the upper straight line and the one that lifts the eyelid. Bottom part represented by three branches, two of which innervate the rectus muscles - the middle and lower, respectively, and the third goes to the lower oblique muscle.
The nuclei lying in front of the aqueduct at the same level as the lower tubercles of the quadruple, create the beginning of the block nerve, which in the area of \u200b\u200bthe roof of the fourth ventricle appears on the surface, forms a cross and stretches to the superior oblique muscle located in the orbit.
From the nuclei located in the cover of the bridge, there are fibers that form the abducens nerve. It has an exit where the middle between the pyramid of the medulla oblongata and the bridge is located, after which it rushes into the orbit to the lateral rectus muscle.
Two components form the 11th, accessory, nerve. The upper one begins in the medulla oblongata - its cerebral nucleus, the lower one - in the dorsal (its upper part), and more specifically, the accessory nucleus, which is localized in the anterior horns. The roots of the lower part, passing through the foramen magnum, go into the cranial cavity and connect to the upper section of the nerve, creating a single trunk. Coming out of the skull, it splits into two branches. The fibers of the upper one grow into fibers of the 10th nerve, and the lower one goes to the sternocleidomastoid and trapezius muscles.
Core hypoglossal nerve is located in the rhomboid fossa (its lower zone), and the roots pass to the surface of the medulla oblongata in the middle of the olive and the pyramid, after which they are combined into a single whole. The nerve emerges from the cranial cavity, then goes to the muscles of the tongue, where it produces 5 terminal branches.
Mixed fiber nerves
The anatomy of this group is complex due to the ramified structure that allows many departments and organs to innervate.
Trigeminal
The area between the middle peduncle of the cerebellum and the bridge is the point of its exit. Core temporal bone forms nerves: orbital, maxillary and mandibular. They have sensitive fibers, motor fibers are added to the latter. The orbital is located in the orbit (upper zone) and branches into the nasal, lacrimal and frontal. The maxillary has an outlet to the surface of the face, after it penetrates the infraorbital space.
The mandibular bifurcates into the anterior (motor) and posterior (sensitive) parts. They provide a neural network:
- the anterior one is split into the chewing, deep temporal, lateral pterygoid and buccal nerves;
- the back - into the middle pterygoid, ear-temporal, inferior alveolar, chin and lingual, each of which is again dismembered into small branches (there are a total of 15 of them).
The mandibular part of the trigeminal nerve is associated with the auricular, submandibular and sublingual nuclei.
The name of this nerve is known more than the other 11 pairs: many are familiar, at least by hearsay, about
The facial nerve is mixed. The motor pathway of the nerve is two-neuronal. The central neuron is located in the cerebral cortex, in the lower third of the precentral gyrus. The axons of the central neurons are directed to the nucleus of the facial nerve, located on the opposite side in the pons of the brain, where the peripheral neurons are located motor path... The axons of these neurons make up the root of the facial nerve.
The facial nerve, passing through the internal auditory opening, is directed to the temporal bone pyramid, located in the facial canal. Further, the nerve leaves the temporal bone through the styloid foramen, entering the parotid salivary gland. In the thickness of the salivary gland, the nerve divides into five branches that form the parotid nerve plexus.
The motor fibers of the VII pair of cranial nerves innervate the facial muscles of the face, the striatus muscle, the muscles of the auricle, the skull, the subcutaneous muscle of the neck, and the digastric muscle (its posterior abdomen).
In the facial canal of the temporal bone pyramid, three branches extend from the facial nerve: the large stony nerve, the staped nerve, the tympanic string.
The large petrosal nerve passes in the pterygopalatine canal and ends in the pterygopalatine node. This nerve innervates the lacrimal gland by forming an anastomosis with the lacrimal nerve after being interrupted in the pterygopalatine node. The large stony nerve includes parasympathetic fibers... The striatal nerve innervates the striatus muscle, causing its tension, which creates conditions for the formation of better hearing.
The drum string innervates the front 2/3 of the tongue, responsible for transmitting impulses with a variety of gustatory stimuli. In addition, the drum string provides parasympathetic innervation of the sublingual and submandibular salivary glands.
Symptoms of defeat. When motor fibers are damaged, peripheral paralysis of the facial muscles develops on the affected side, which is manifested by facial asymmetry: half of the face on the side of the nerve lesion becomes immobile, mask-like, the frontal and nasolabial folds are smoothed, the eye on the affected side does not close, the palpebral fissure expands, the angle of the mouth is lowered down ...
Bell's phenomenon is noted - turning the eyeball upward when trying to close the eye on the affected side. Paralytic lacrimation is observed due to the absence of blinking. Isolated paralysis of the facial muscles is characteristic of damage to the motor nucleus of the facial nerve.
In the case of attachment of the lesion of the pyramidal fibers to the clinical symptoms of peripheral palsy of the facial nerve, Miyard-Gübler syndrome is formed with central paralysis of the limbs on the side opposite to the lesion of the facial nerve).
With the defeat of the facial nerve in the cerebellopontine angle, in addition to paralysis of the facial muscles, there is a decrease in hearing or deafness, the absence of a corneal reflex, which indicates a simultaneous damage to the auditory and trigeminal nerves. This pathology occurs with inflammation of the cerebellopontine angle (arachnoiditis), neuroma of the auditory nerve. The accession of hyperacusis and a violation of taste indicate damage to the nerve before the large petrosal nerve leaves it in the facial canal of the temporal bone pyramid.
The defeat of the nerve above the tympanic string, but below the discharge of the staped nerve is characterized by a taste disorder, lacrimation.
Paralysis of mimic muscles in combination with lacrimation occurs when the facial nerve is damaged below the discharge of the tympanic string.
Only the cortical-nuclear pathway may be affected. Clinically, there is paralysis of the muscles of the lower half of the face in combination with hemiparesis on the side opposite to the focus.
VIII pair of cranial nerves - vestibular cochlear nerve
The nerve includes two roots: the cochlear, which is the lower, and the vestibule, which is the upper root.
Cochlear nerve is sensitive, auditory. It starts from the cells of the spiral node, in the cochlea of \u200b\u200bthe labyrinth. The dendrites of the cells of the spiral node go to the auditory receptors - the hair cells of the organ of Corti.
The axons of the cells of the spiral node are located in the internal auditory canal. The nerve passes in the pyramid of the temporal bone, then enters the brain stem at the level of the upper part of the medulla oblongata, ending in the nuclei of the cochlear part (anterior and posterior). Most of the axons from the nerve cells of the anterior cochlear nucleus cross, passing to the other side of the brain bridge. A minority of axons are not involved in crossing.
The axons end on the cells of the trapezius body and the upper olive on both sides. Axons from these structures of the brain make up a lateral loop ending in the quadruple and on the cells of the medial geniculate body. The axons of the posterior cochlear nucleus cross in the midline of the bottom of the IV ventricle.
On the opposite side, the fibers are connected to the axons of the lateral loop. The axons of the posterior cochlear nucleus end in the lower mounds of the quadruple. The part of the axons of the posterior nucleus, not participating in the crossover, is connected to the fibers of the lateral loop on its side.
Symptoms of defeat.
With damage to the nerve at various levels, auditory hallucinations, irritation symptoms, hearing loss, and deafness may appear. Decreased hearing acuity or deafness on one side occurs when the nerve is damaged at the receptor level, when the cochlear part of the nerve and its anterior or posterior nuclei are damaged.
Symptoms of irritation in the form of a whistling sensation, noise, crackling may also be added. This is due to irritation of the cortex of the middle part of the superior temporal gyrus by various pathological processes in this area, for example, tumors.
The vestibule part. In the internal auditory canal there is a vestibular node formed by the first neurons of the pathway of the vestibular analyzer. Dendrites of neurons form receptors in the labyrinth of the inner ear, located in the membranous sacs and in the ampullae of the semicircular canals.
The axons of the first neurons constitute the vestibular part of the VIII pair of cranial nerves, located in the temporal bone and entering through the internal auditory opening into the brain substance in the region of the cerebellopontine angle. The nerve fibers of the vestibular part end on the neurons of the vestibular nuclei, which are the second neurons of the pathway of the vestibular analyzer. The nuclei of the vestibular part are located at the bottom of the V ventricle, in its lateral part, and are represented by the lateral, medial, superior, and inferior.
The neurons of the lateral nucleus of the vestibular part give rise to the vestibular-spinal pathway, which is part of the spinal cord and ends on the neurons of the anterior horns.
The axons of the neurons of this nucleus form a medial longitudinal bundle located in the spinal cord on both sides. The course of fibers in the bundle has two directions: descending and ascending. Descending nerve fibers are involved in the formation of a part of the anterior cord. The ascending fibers rise to the nucleus of the oculomotor nerve. The fibers of the medial longitudinal bundle are connected with the nuclei of the III, IV, VI pairs of cranial nerves, due to which impulses from the semicircular canals are transmitted to the nuclei of the oculomotor nerves, causing the movement of the eyeballs when the position of the body in space changes. There are also two-way connections with the cerebellum, reticular formation, posterior nucleus vagus nerve.
Symptoms of damage are characterized by the following triad: dizziness, nystagmus, impaired coordination of movement. There is a vestibular ataxia, manifested by a shaky gait, a deviation of the patient towards the lesion. Dizziness is characterized by seizures lasting up to several hours, which may be accompanied by nausea and vomiting. The attack is accompanied by horizontal or horizontal rotator nystagmus. When a nerve is damaged on one side, nystagmus develops in the direction opposite to the lesion. With irritation of the vestibular part, nystagmus develops in the direction of the lesion.
Peripheral lesions of the vestibular cochlear nerve can be of two types: labyrinthine and radicular syndromes. In both cases, there is a simultaneous violation of the functioning of the auditory and vestibular analyzer. Radicular syndrome of peripheral lesion of the vestibular cochlear nerve is characterized by the absence of dizziness, but may be manifested by imbalance.
IX pair of cranial nerves - glossopharyngeal nerve
This nerve is mixed. The sensory pathway of the nerve is three-neuronal. The bodies of the first neurons are located in the nodes of the glossopharyngeal nerve. Their dendrites end with receptors in the posterior third of the tongue, soft palate, pharynx, pharynx, auditory tube, tympanic cavity, anterior surface of the epiglottis.
The axons of the first neurons enter the brain behind the olive and end on the cells of the nucleus of the solitary pathway, which are the second neurons. Their axons intersect, ending at the cells of the thalamus, where the bodies of third neurons are located. Axons of third neurons pass through the posterior pedicle of the inner capsule and end in the cells of the cortex of the lower part of the postcentral gyrus.
The motor pathway is two-neural. The first neuron is located in the lower part of the precentral gyrus. Its axons end on cells of the double nucleus on both sides, where the second neurons are located. Their axons innervate fibers of the stylopharyngeal muscle. Parasympathetic fibers originate from the cells of the anterior part of the hypothalamus, ending on the cells of the lower salivary nucleus. Their axons form the tympanic nerve, which is part of the tympanic plexus. The fibers end on the cells of the ear node, the axons of which innervate the parotid salivary gland.
Symptoms of the lesion include a violation of taste in the posterior third of the tongue, loss of sensitivity in the upper half of the pharynx, and gustatory hallucinations that develop when the cortical projection areas located in the temporal lobe of the brain are irritated. Irritation of the nerve itself is manifested by burning, varying intensity pains in the area of \u200b\u200bthe root of the tongue and tonsils lasting 1-2 minutes, radiating to palatine curtain, throat, ear. The pain provokes talking, eating, laughing, yawning, head movement. A characteristic symptom of neuralgia in the interictal period is pain around the angle of the mandible on palpation.
X pair of cranial nerves - vagus nerve
The vagus nerve is mixed. The sensitive pathway is three-neuronal. The first neurons form the nodes of the vagus nerve. Their dendrites end in receptors on the dura mater of the posterior cranial fossa, the mucous membrane of the pharynx, larynx, upper trachea, internal organs, the skin of the auricle, the posterior wall of the external auditory canal. The axons of the first neurons end on the cells of the nucleus of the solitary pathway in the medulla oblongata, which are the second neurons. Their axons end on cells in the thalamus, which are the third neurons. Axons of third neurons pass through the inner capsule, terminating in the cells of the cortex of the postcentral gyrus.
The motor pathway begins in the cells of the cortex of the precentral gyrus. Their axons end on the cells of the second neurons located in the double nucleus. The axons of the second neurons innervate the soft palate, larynx, epiglottis, the upper part of the esophagus, and the striated muscles of the pharynx.
The autonomic nerve fibers of the vagus nerve are parasympathetic. They start from the nuclei of the anterior part of the hypothalamus, ending in the vegetative dorsal nucleus. Axons from neurons of the dorsal nucleus are directed to the myocardium, smooth muscles of internal organs and blood vessels.
Symptoms of defeat.
With damage to the vagus nerve, paralysis of the muscles of the pharynx and esophagus develops, a violation of swallowing, leading to the ingress of liquid food into the nose. The patient develops a nasal tone of voice, he becomes hoarse, which is explained by paralysis vocal cords... In the case of bilateral lesions of the vagus nerve, aphonia and suffocation may develop. When the vagus nerve is damaged, the activity of the heart muscle is disrupted, which is manifested by tachycardia or bradycardia when it is irritated. These disorders of the heart will be expressed in bilateral lesions. In this case, a pronounced violation of breathing, phonation, swallowing, cardiac activity develops.
XI pair of cranial nerves - accessory nerve
The motor pathway of the accessory nerve is bineuronal. The first neuron is located in the lower part of the precentral gyrus. Its axons enter the brain stem, pons, medulla oblongata, passing through the inner capsule and ending at the level of the anterior horns CI – CV of the spinal cord on both sides.
The fibers of the second neuron leave the spinal cord at the CI – CV level, forming a common trunk, which enters the cranial cavity through the foramen magnum. There, the common trunk connects with the fibers of the motor double nucleus of the X pair of cranial nerves and together with them leaves the cranial cavity through the jugular opening. After the exit of the fibers of the accessory nerve, the trapezius and sternocleidomastoid muscles are innervated.
Symptoms of defeat.
With unilateral damage to the nerve, it is difficult to lift the shoulders, the turn of the head in the direction opposite to the lesion is sharply limited. In this case, the head deviates towards the affected nerve. With bilateral nerve damage, it is impossible to make head turns in both directions, the head is thrown back.
When the nerve is irritated, a muscle spasm of a tonic character develops, which is manifested by the appearance of spastic torticollis (the head is turned in the direction opposite to the lesion). With bilateral irritation, clonic convulsions of the sternocleidomastoid muscles develop, which is manifested by hyperkinesis with the appearance of nodding movements of the head.
XII pair of cranial nerves - hypoglossal nerve
The nerve is purely motor. The pathway consists of two neurons. The central neuron is located in the cortex of the lower third of the precentral gyrus. The fibers of the central neurons end on the cells of the hypoglossal nerve nucleus from the opposite side, passing before this through the inner capsule of the brain in the region of the pons knee, the medulla oblongata.
Nuclear cells of the XII pair of cranial nerves are peripheral neurons of the pathway. The hypoglossal nerve nucleus is located at the bottom of the rhomboid fossa in the medulla oblongata. Fibers of the second neurons of the motor pathway pass through the substance of the medulla oblongata, and then leave it, leaving in the area between the olive and the pyramid.
The motor fibers of the XII pair provide innervation to the muscles located in the thickness of the tongue itself, as well as the muscles that move the tongue forward and down, up and back.
Symptoms of defeat.
If the hypoglossal nerve is damaged at various levels, peripheral or central paralysis (paresis) of the muscles of the tongue may occur. Peripheral paralysis or paresis develops when the nucleus of the hypoglossal nerve or nerve fibers emanating from this nucleus are damaged.
In this case, clinical manifestations develop in half of the muscles of the tongue from the side corresponding to the lesion. Unilateral damage to the hypoglossal nerve leads to a slight decrease in the function of the tongue, which is associated with the interlacing of the muscle fibers of both its halves.
More severe is bilateral nerve damage, characterized by glossoplegia (paralysis of the tongue). In case of damage to a section of the pathway from the central to the peripheral neuron, central paralysis of the muscles of the tongue develops. In this case, there is a deviation of the tongue in the direction opposite to the defeat. Central paralysis of the muscles of the tongue is often combined with paralysis (paresis) of the muscles of the upper and lower extremities on the same side.
VII pair - facial nerve (n. Facialis). It is a mixed nerve. It contains motor, parasympathetic and sensory fibers, the last two types of fibers are isolated as an intermediate nerve.
The motor part of the facial nerve provides innervation to all facial muscles face, muscles of the auricle, skull, posterior abdomen of the digastric muscle, stapes muscle and subcutaneous muscle of the neck.
In the facial canal, a number of branches leave the facial nerve.
1. The greater petrosal nerve from the knee node at the outer base of the skull connects to the deep petrosal nerve (a branch of the sympathetic plexus of the internal carotid artery) and forms the nerve of the pterygoid canal, which enters the pterygo-palatine canal and reaches the pterygopalatine node. The connection of the large stony nerve and the deep stony nerve is the so-called Vidian nerve. The nerve contains preganglionic parasympathetic fibers to the pterygopalatine node, as well as sensory fibers from the cells of the knee node. With its defeat, a peculiar symptom complex arises, known as neuralgia of the vidian nerve (File's syndrome). The large petrosal nerve innervates the lacrimal gland. After a break in the pterygopalatine node, the fibers go as part of the maxillary and then the zygomatic nerves, anastomose with the lacrimal nerve, which approaches the lacrimal gland. With the defeat of the large stony nerve, dryness of the eye occurs due to a violation of the secretion of the lacrimal gland, with irritation - lacrimation.
2. The streptococcal nerve penetrates into tympanic cavity and innervates the striatus muscle. When this muscle is strained, conditions are created for the best audibility. If the innervation is disturbed, paralysis of the striatus muscle occurs, as a result of which the perception of all sounds becomes sharp, causing painful, unpleasant sensations (hyperacusis).
3. The tympanic string is separated from the facial nerve in the lower part of the facial canal, enters the tympanic cavity and through the petrotympanic fissure goes to the outer base of the skull and merges with the lingual nerve. At the intersection with the inferior alveolar nerve, the tympanic string gives off a connecting branch to the ear node, in which motor fibers pass from the facial nerve to the muscle that lifts the soft palate.
The tympanic string transmits gustatory stimuli from the anterior two-thirds of the tongue to the knee node and then to the nucleus of the solitary pathway, to which the taste fibers of the glossopharyngeal nerve fit. As part of the drum string, secretory salivary fibers also pass from the upper salivary nucleus to the submandibular and sublingual salivary glands, preliminarily interrupting in the submandibular and sublingual parasympathetic nodes.
With the defeat of the facial nerve, the asymmetry of the face immediately attracts attention. Usually, mimic muscles are examined during motor load. The examinee is offered to raise his eyebrows, frown, close his eyes. Pay attention to the severity of the nasolabial folds and the position of the corners of the mouth. They are asked to show teeth (or gums), puff out cheeks, blow out a candle, whistle. A number of tests are used to detect mild muscle paresis.
Blink test: the eyes blink asynchronously due to the slowed blinking on the paresis side.
Eyelid vibration test: when the eyes are closed, the eyelid vibration is either reduced or absent on the side of paresis, which is determined by a light touch of the fingers to the closed eyelids at the outer corners of the eye (especially when the eyelids are pulled backward).
Test of the study of the circular muscle of the mouth: on the side of the lesion, the strip of paper is held weaker by the corner of the lips.
Symptom of eyelashes: on the affected side with the eyes closed as much as possible, the eyelashes are visible better than on the healthy, due to insufficient closure of the circular muscle of the eye.
For the differentiation of central and peripheral paresis, the study of electroexcitability, as well as electromyography, is important.
Loss of taste sensitivity is called ageusia, lowering it - hypogeusia, increasing taste sensitivity - hypergeusia, its perversion - parageusia.
Symptoms of defeat. When the motor part of the facial nerve is damaged, peripheral paralysis of the facial muscles develops - the so-called prosoplegia. Facial asymmetry occurs. The entire affected half of the face is motionless, mask-like, the folds of the forehead and the nasolabial fold are smoothed, the palpebral fissure expands, the eye does not close (lagophthalmos is the hare's eye), the corner of the mouth drops. Wrinkling the forehead does not create wrinkles. When trying to close the eye, the eyeball turns upward (Bell's phenomenon). There is increased lacrimation. At the heart of paralytic lacrimation is constant irritation of the mucous membrane of the eye with a stream of air and dust. In addition, as a result of paralysis of the circular muscle of the eye and insufficient adhesion of the lower eyelid to eyeball a capillary gap is not formed between the lower eyelid and the mucous membrane of the eye, which makes it difficult for the tear to move to the lacrimal canal. Due to the displacement of the opening of the lacrimal canal, the absorption of tears through the lacrimal canal is disturbed. This is facilitated by paralysis of the circular muscle of the eye and the loss of the blink reflex. Constant irritation of the conjunctiva and cornea with a stream of air and dust leads to the development of inflammatory phenomena - conjunctivitis and keratitis.
For medical practice, it is important to determine the location of the lesion of the facial nerve. In the event that the motor nucleus of the facial nerve is affected (for example, in the pontine form of poliomyelitis), only facial muscle paralysis occurs. If the nucleus and its radicular fibers are affected, the nearby pyramidal pathway is often involved in the process and, in addition to the paralysis of the facial muscles, central paralysis (paresis) of the extremities of the opposite side occurs (Miyard-Gubler syndrome). With a simultaneous lesion of the nucleus of the abducent nerve, there is also a converging squint on the side of the lesion or paralysis of the gaze towards the focus (Fauville syndrome). If at the same time the sensitive pathways at the level of the nucleus suffer, then hemianesthesia develops on the side opposite to the focus. If the facial nerve is affected at the site of its exit from the brain stem in the cerebellopontine angle, which is often the case with inflammatory processes in this area (arachnoiditis of the cerebellopontine angle) or neuroma of the auditory nerve, then the paralysis of the facial muscles is combined with symptoms of auditory damage (hearing loss or deafness) and trigeminal (lack of corneal reflex) nerves. Since the conduction of impulses along the fibers of the intermediate nerve is disturbed, dryness of the eye (xerophthalmia) occurs, taste is lost on the front two-thirds of the tongue on the side of the lesion. In this case, xerostomia should develop, but due to the fact that other salivary glands are functioning, dryness in the oral cavity is not noted. There is no hyperacusis, which theoretically exists, but due to the combined lesion of the auditory nerve is not detected.
The defeat of the nerve in the facial canal up to its knee above the discharge of the large stony nerve leads, simultaneously with facial paralysis, to dryness of the eye, taste disorder and hyperacusis. If the nerve is affected after the departure of the large stony and staped nerves, but above the discharge of the drum string, then mimic paralysis, lacrimation and taste disorders are determined. With the defeat of the VII pair in the bone canal below the discharge of the tympanic string or when leaving the styloid foramen, only mimic paralysis with lacrimation occurs. The most common lesion of the facial nerve at the exit from the facial canal and after exiting the skull. Possible bilateral damage to the facial nerve, and even recurrent.
In cases where the cortical-nuclear pathway is affected, paralysis of the facial muscles occurs only in the lower half of the face on the side opposite to the lesion focus. Often, hemiplegia (or hemiparesis) also occurs on this side. The peculiarities of paralysis are explained by the fact that the part of the facial nerve nucleus, which is related to the innervation of the muscles of the upper half of the face, receives bilateral cortical innervation, and the rest is unilateral.
VIII pair - vestibular cochlear nerve (item vestibulocochlea-ris). Consists of two roots: lower - cochlear and upper - vestibule. Symptoms of defeat. Hearing loss, increased perception of sounds, ringing, tinnitus, auditory hallucinations. After that, hearing acuity is determined.When hearing loss (hypacusia) or loss (anacusia), it is necessary to determine whether it depends on the defeat of the sound-conducting (external auditory canal, middle ear) or sound-receiving (organ of Corti, cochlear part VIII nerve and its core) apparatus. To distinguish the lesion of the middle ear from the lesion of the cochlear part of the VIII nerve, tuning forks (Rinne and Weber's method) or audiometry are used. the peripheral hearing aid turns out to be in communication with both hemispheres of the brain, then the defeat of the auditory conductors above the anterior and posterior auditory nuclei does not cause loss of auditory functions. Unilateral hearing loss or deafness is possible only with damage to the receptor hearing system, cochlear nerve and its nuclei. In this case, there may be symptoms of irritation (sensation of noise, whistling, hum, crackling, etc.). When the temporal lobe cortex is irritated (for example, with tumors), auditory hallucinations can occur.
The vestibule (pars vestibularis).
Symptoms of defeat. The defeat of the vestibular apparatus - the labyrinth, the vestibular part of the VIII nerve and its nuclei - leads to three characteristic symptoms: dizziness, nystagmus and coordination disorder. The conscious and automatic orientation in space is impaired: the patient has false sensations of displacement of his own body and surrounding objects. Dizziness often occurs with attacks, reaches a very strong degree, can be accompanied by nausea, vomiting .. Rarely, nystagmus is expressed when looking directly; it is usually better seen when looking to the side. Irritation of the vestibular part of the VIII nerve and its nuclei causes nystagmus in the same direction. Turning off the vestibular apparatus leads to nystagmus in the opposite direction.
The defeat of the vestibular apparatus is accompanied by abnormal reactive movements, disruption of the normal tone of muscles and their antagonists. Movements are deprived of the proper regulatory influences - hence the discoordination of movements (vestibular ataxia). A shaky gait appears, the patient deviates in the direction of the affected labyrinth, and in this direction he often falls.
Dizziness, nystagmus and ataxia can be observed with damage not only to the vestibular apparatus, but also to the cerebellum, therefore it is important to differentiate labyrinthine lesions from similar cerebellar symptoms. Diagnosis is based on the following data: 1) dizziness during labyrinthitis is extremely intense; 2) in Romberg's test, the body tilts to the side with closed eyes, and there is a dependence on the position of the head and the affected labyrinth; 3) ataxia is always general, that is, it is not limited to only one limb or the limbs of one side, it is not accompanied by intentional tremors, as is observed in cerebellar ataxia; 4) nystagmus in labyrinthine lesions is characterized by a pronounced fast and slow phase and has a horizontal or rotatory direction, but not vertical; 5) labyrinthine lesions are usually associated with symptoms of damage to the hearing aid (eg, noise in the ear, hearing loss).
2.37 Symptoms of damage to 9 and 10 pairs of cranial nerves.
Glossopharyngeal and vagus nerves (n. Glossopharyngeus et n. Vagus). They have common nuclei, which are laid in the medulla oblongata in one place, therefore, they are studied simultaneously.
IX pair - glossopharyngeal nerve (item glossopharyngeus). Contains 4 types of fibers: sensory, motor, gustatory and secretory. Sensitive innervation of the posterior third of the tongue, soft palate, pharynx, pharynx, anterior surface of the epiglottis, auditory tube and tympanic cavity. Motor fibers innervate the stylopharyngeal muscle, which lifts upper part pharynx when swallowing.
Parasympathetic fibers innervate the parotid gland.
Symptoms of defeat. When the glossopharyngeal nerve is damaged, taste disorders are observed in the posterior third of the tongue (hypogeusia or ageusia), loss of sensitivity in the upper half of the pharynx; disorders of motor function are not clinically expressed due to the insignificant functional role of shiloglo-
exact muscle. Irritation of the cortical projection area in the deep structures of the temporal lobe leads to the appearance of false taste sensations (parageusia). They can sometimes be the harbingers (aura) of an epileptic seizure. Irritation of the IX nerve causes pain in the root of the tongue or tonsil, spreading to the palatine curtain, throat, ear.
X pair - vagus nerve (n. Vagus). Contains sensitive, motor and vegetative fibers. Provides sensory innervation to the dura mater of the posterior cranial fossa, the posterior wall of the external auditory canal and part of the skin of the auricle, mucous membrane of the pharynx, larynx, upper trachea and internal organs Motor fibers innervate the striated muscles of the pharynx, soft palate, larynx, epiglottis, and upper esophagus.
Vegetative (parasympathetic) fibers go to the heart muscle, smooth muscle tissue of blood vessels and internal organs. The impulses traveling along these fibers slow down the heartbeat, dilate blood vessels, narrow the bronchi, and increase intestinal motility. Postganglionic sympathetic fibers from the cells of the paravertebral sympathetic nodes also enter the vagus nerve and spread along the branches of the vagus nerve to the heart, blood vessels and internal organs.
Symptoms of defeat. When the periphery of the vagus neuron is damaged, swallowing is impaired due to paralysis of the muscles of the pharynx and esophagus. It is noted that liquid food gets into the nose in the result of paralysis of the palatine muscles, the soft palate hangs down on the affected side. With paralysis of the voice of the ligaments, the sonority of the voice is weakened, with bilateral damage, up to aphonia and suffocation. Symptoms of a lesion of the vagus include a disorder of cardiac activity - tachycardia and bradycardia (with irritation). With unilateral lesion, we are not very pronounced, with bilateral - pronounced disorders of swallowing, phonation, breathing and heart activity. With the defeat of the senses of the branches of the vagus, the feeling of the mucus of the larynx, pain in the larynx and ear is disturbed. With the defeat of 9 pairs, the taste for bitter and salty on the back of a third of the tongue is lost, as well as the feeling of mucus from the upper part of the pharynx.
What structures are attributed to the peripheral nervous system of a person? 1) spinal nerves 2) forebrain 3) nerve nodes 4) spinal cord 5)cranial nerves 6) medulla oblongata
Grade 8 BiologyOption 3
Level A
1. Indicate the central, main part of the cell?
1) ribosomes; 2) cytoplasm; 3) the core.
2. Which of these processes in cell division occurs first?
1) nuclear fission; 2) self-duplication of chromosomes;
3) doubling of the cell center.
3. What tissue is used for nails and hair?
1) epithelial; 2) connecting; 3) muscular.
4. What is the name of the liquid part of blood?
1) lymph; 2) plasma; 3) water.
5. What soluble plasma protein is involved in clotting?
1) hemoglobin; 2) fibrin; 3) fibrinogen.
6. What features of the structure of leukocytes correspond to their function?
1) small, there are many of them, a large common surface;
2) the presence of pseudopods, the ability to move;
3) flat shape, contributing to the rapid absorption of gas.
7. What vessels have valves inside?
1) veins; 2) arteries; 3) capillaries.
8. What is the indicator of heart development?
1) an increase in heart mass; 2) an increase in the volume of the heart;
3) an increase in the fibers of the heart muscle.
9. What is the state of the heart valves during contraction
atria?
1) the semilunar valves are open, the leaf valves are closed;
2) the semilunar valves are closed, the leaf valves are open;
3) all valves are open.
10. What human bones are most developed in connection with physical
labor?
1) hand bones; 2) the bones of the forearm; 3) the femur.
11. What tissue are skeletal muscles made of?
1) smooth muscle; 2) cross-striped; 3) connecting.
12. What physiological processes occur in muscle cells
fabrics?
1) intake of О2 and release of СО2;
2) the entry of organic substances and O2 into the cell;
3) intake of organic matter and O2, oxidation and decomposition, removal
CO2.
14. Indicate the processes - sources of energy in the body:
1) synthesis of organic substances; 2) diffusion;
3) oxidation of organic substances.
Level B:
1. How many lobes are the cerebral hemispheres divided into?
2. What vitamin should be given to a patient with scurvy?
3. How many semicircular canals does the balance organ have?
4. How many cervical vertebrae does a person have?
5. How many pairs of cranial nerves does a person have?
Level C:
1. Does mental capacity depend on the mass of the brain?
2. Why do they say that the eye looks and the brain sees?
1) Central
B) Nerve nodes 2) Peripheral
C) Spinal cord
D) Brain
D) nerve endings
E) cranial nerves
What structures are attributed to the peripheral nervous system of a person? Choose three correct answers out of six and write down the numbers under which they are indicated. one)spinal nerves 2) forebrain 3) nerve nodes 4) spinal cord 5) cranial nerves 6) medulla oblongata
In spiders and echinoderms, digestion: a. Intracavitary, b. Intracellular, c. Outside, d. There is no right answer.Complication digestive system followed the path: a. Complications of the digestive glands, b. Extending it, in. Increases in the suction surface, d. All of the above.
Substances that accelerate all reactions in the body are called: a. Digestive juices, b. Vitamins, c. Exchange products, Enzymes.
The ladder-type nervous system is developed in: a. Annelids, b. Hydras, in. Arthropods, Planaria.
Compared to reptiles, birds have the most developed part of the brain: a. Diencephalon, c. Large hemispheres, c. Cranial nerves, d. All of the above.
In which organ of the mammalian circulatory system is the blood saturated with oxygen? A. In the veins of the small circle, b. In capillaries large circle, in. In the veins of the great circle, d. In the capillaries of the small circle.
In which part of the digestive system is the absorption of nutrients? A. In the large intestine, b. In the stomach, in. IN small intestine, d. In the rectum.
Help please, I'm just home schooled teachers rarely come because they are busy.
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VI pair - abducens nerves
Abducens nerve (item abducens) - motor. Abducens nerve nucleus (nucleus n. abducentis) located in front of the bottom of the IV ventricle. The nerve leaves the brain at the posterior edge of the bridge, between it and the pyramid of the medulla oblongata, and soon outside of the back of the sella turcica enters the cavernous sinus, where it is located along the outer surface of the internal carotid artery (Fig. 1). Then it penetrates through the superior orbital fissure into the orbit and follows forward above the oculomotor nerve. It innervates the external rectus muscle of the eye.
Figure: 1. Nerves of the oculomotor apparatus (diagram):
1 - superior oblique muscle of the eye; 2 - superior rectus muscle of the eye; 3 - trochlear nerve; 4 - the oculomotor nerve; 5 - lateral rectus muscle of the eye; 6 - lower rectus muscle of the eye; 7 - abducens nerve; 8 - lower oblique muscle of the eye; 9 - medial rectus muscle of the eye
VII pair - facial nerves
(n. facialis) develops in connection with the formations of the second branchial arch, so it innervates all the muscles of the face (mimic). The nerve is mixed, including motor fibers from its efferent nucleus, as well as sensory and autonomic (taste and secretory) fibers belonging to the closely associated with the facial intermediate nerve (n. intermedius).
Motor nucleus of the facial nerve (nucleus n. facialis) is located at the bottom of the IV ventricle, in the lateral region reticular formation... The root of the facial nerve leaves the brain together with the root of the intermediate nerve in front of the vestibular cochlear nerve, between the posterior edge of the pons and the olive of the medulla oblongata. Further, the facial and intermediate nerves enter the internal auditory opening and enter the facial nerve canal. Here, both nerves form a common trunk, making two turns in accordance with the bends of the canal (Fig. 2, 3).
Figure: 2. Facial nerve (diagram):
1 - internal sleepy plexus; 2 - knee knot; 3 - facial nerve; 4 - facial nerve in the internal auditory canal; 5 - intermediate nerve; 6 - motor nucleus of the facial nerve; 7 - upper salivary nucleus; 8 - the core of a single path; 9 - the occipital branch of the posterior auricular nerve; 10 - branches to the ear muscles; 11 - posterior ear nerve; 12 - nerve to the stryschkovy muscle; 13 - styloid opening; 14 - tympanic plexus; 15 - tympanic nerve; 16 - glossopharyngeal nerve; 17 - back abdomen of the digastric muscle; 18 - stylohyoid muscle; 19 - drum string; 20 - lingual nerve (from the mandibular); 21 - submandibular salivary gland; 22 - sublingual salivary gland; 23 - submandibular node; 24 - pterygopalatine node; 25 - ear node; 26 - nerve of the pterygoid canal; 27 - small stony nerve; 28 - deep stony nerve; 29 - large stony nerve
Figure: 3
I - large stony nerve; 2 - knot of the knee of the facial nerve; 3 - facial canal; 4 - tympanic cavity; 5 - drum string; 6 - hammer; 7 - anvil; 8 - semicircular tubules; 9 - spherical pouch; 10 - elliptical pouch; 11 - vestibule node; 12 - internal auditory canal; 13 - the nucleus of the cochlear nerve; 14 - lower cerebellar pedicle; 15 - nuclei of the pre-door nerve; 16 - medulla oblongata; 17 - vestibular cochlear nerve; 18 - motor portion of the facial nerve and intermediate nerve; 19 - cochlear nerve; 20 - vestibular nerve; 21 - spiral ganglion
First, the common trunk is located horizontally, heading over the tympanic cavity anteriorly and laterally. Then, according to the bend of the facial canal, the trunk turns at a right angle backward, forming a knee (geniculum n. Facialis) and a knee node (ganglion geniculi), belonging to the intermediate nerve. Having passed over the tympanic cavity, the trunk makes a second downward turn, located behind the middle ear cavity. In this section, branches of the intermediate nerve depart from the common trunk, the facial nerve leaves the canal through the styloid opening and soon enters the parotid salivary gland.The length of the trunk of the extracranial part of the facial nerve ranges from 0.8 to 2.3 cm (usually 1.5 cm), and thickness - from 0.7 to 1.4 mm: the nerve contains 3500-9500 myelinated nerve fibers, among which thick ones predominate.
In the parotid salivary gland, at a depth of 0.5-1.0 cm from its outer surface, the facial nerve is divided into 2-5 primary branches, which are divided into secondary branches, forming parotid plexus (plexus intraparotideus) (fig. 4).
Figure: 4.
a - the main branches of the facial nerve, right side view: 1 - temporal branches; 2 - zygomatic branches; 3 - parotid duct; 4 - buccal branches; 5 - marginal branch of the lower jaw; 6 - cervical branch; 7 - digastric and stylohyoid branches; 8 - the main trunk of the facial nerve at the exit from the styloid foramen; 9 - posterior ear nerve; 10 - parotid salivary gland;
b - facial nerve and parotid gland on a horizontal section: 1 - medial pterygoid muscle; 2 - a branch of the lower jaw; 3 - chewing muscle; 4 - parotid salivary gland; 5 - mastoid process; 6 - the main trunk of the facial nerve;
c - three-dimensional diagram of the relationship between the facial nerve and the parotid salivary gland: 1 - temporal branches; 2 - zygomatic branches; 3 - buccal branches; 4 - marginal branch of the lower jaw; 5 - cervical branch; 6 - the lower branch of the facial nerve; 7 - digastric and stylohyoid branches of the facial nerve; 8 - the main trunk of the facial nerve; 9 - posterior ear nerve; 10 - the upper branch of the facial nerve
There are two forms of the external structure of the parotid plexus: reticular and trunk. When reticular the trunk of the nerve is short (0.8-1.5 cm), in the thickness of the gland it is divided into many branches, which have multiple connections among themselves, as a result of which a narrow-looped plexus is formed. There are multiple connections with the branches of the trigeminal nerve. When main form the trunk of the nerve is relatively long (1.5-2.3 cm), it is divided into two branches (upper and lower), which give several secondary branches; there are few connections between secondary branches, the plexus is wide-looped (Fig. 5).
Figure: five.
a - network-like structure; b - main structure;
1 - facial nerve; 2 - chewing muscle
On its way, the facial nerve gives off branches when passing through the canal, as well as after leaving it. A number of branches extend from it inside the channel:
1. Large stony nerve (item petrosus major) originates near the knee node, leaves the canal of the facial nerve through the cleft of the canal of the greater petrosal nerve and passes along the groove of the same name to the lacerated opening. Having penetrated through the cartilage to the outer base of the skull, the nerve connects to the deep petrosal nerve, forming pterygoid nerve (n. canalis pterygoidei)entering the pterygoid canal and reaching the pterygopalatine node.
The greater petrosal nerve contains parasympathetic fibers to the pterygopalatine node, as well as sensory fibers from the cells of the knee node.
2. The stapes nerve (n. Stapedius) - a thin trunk, branches off in the canal of the facial nerve at the second turn, penetrates into the tympanic cavity, where it innervates the stapedius muscle.
3. Drum string (chorda tympani) is a continuation of the intermediate nerve, is separated from the facial nerve in the lower part of the canal above the styloid opening and enters through the tubule of the tympanic string into the tympanic cavity, where it lies under the mucous membrane between the long leg of the incus and the handle of the hammer. Through the petrotympanic fissure, the tympanic string exits to the outer base of the skull and merges with the lingual nerve in the infratemporal fossa.
At the intersection with the inferior alveolar nerve, the tympanic string gives a connecting branch with the ear node. The tympanic string consists of preganglionic parasympathetic fibers to the submandibular ganglion and taste sensory fibers to the anterior two-thirds of the tongue.
4. Connecting branch with tympanic plexus (r. communicans cum plexus tympanico) - thin branch; starts from the knee node or from the large stony nerve, passes through the roof of the tympanic cavity to the tympanic plexus.
Upon exit from the canal, the following branches extend from the facial nerve.
1. Posterior ear nerve (item auricularis posterior) departs from the facial nerve immediately after leaving the styloid foramen, goes back and up along the front surface of the mastoid process, dividing into two branches: the ear (r. auricularis), which innervates the posterior ear muscle, and occipital (r. occipitalis)innervating the occipital abdomen of the supracranial muscle.
2. Digastric branch (r. digasricus) occurs slightly below the ear nerve and, going down, innervates the posterior abdomen of the digastric muscle and the stylohyoid muscle.
3. Connecting branch with glossopharyngeal nerve (r. communicans cum nervo glossopharyngeo) branches off near the styloid foramen and spreads anteriorly and downward along the stylopharyngeal muscle, connecting with the branches of the glossopharyngeal nerve.
Parotid plexus branches:
1. The temporal branches (rr. Temporales) (2-4 in number) go up and are divided into 3 groups: the anterior, innervating the upper part of the circular muscle of the eye, and the muscle wrinkling the eyebrow; middle, innervating the frontal muscle; posterior, innervating rudimentary muscles of the auricle.
2. Zygomatic branches (rr. Zygomatici) (3-4 in number) extend forward and upward to the lower and lateral parts of the circular muscle of the eye and the zygomatic muscle, which innervate.
3. Buccal branches (rr. Buccales) (3-5 in number) run horizontally anteriorly along the outer surface of the masseter muscle and supply the muscles with branches around the nose and mouth.
4. Marginal branch of the lower jaw (r. marginalis mandibularis) runs along the edge of the lower jaw and innervates the muscles that lower the corner of the mouth and lower lip, the chin muscle and the muscle of laughter.
5. The cervical branch (r. Colli) descends to the neck, connects to the transverse nerve of the neck and innervates the so-called platysma.
Intermediate nerve (item intermedins) consists of preganglionic parasympathetic and sensory fibers. Sensitive unipolar cells are located at the knee node. The central processes of the cells ascend as part of the nerve root and end in the nucleus of the solitary pathway. Peripheral processes of sensory cells go through the tympanic cord and the large petrosal nerve to the mucous membrane of the tongue and soft palate.
Secretory parasympathetic fibers originate in the superior salivary nucleus in the medulla oblongata. The root of the intermediate nerve leaves the brain between the facial and vestibular cochlear nerves, joins the facial nerve and goes into the facial nerve canal. The fibers of the intermediate nerve leave the trunk of the facial, passing into the tympanic string and the large stony nerve, reaching the submandibular, hyoid and pterygopalatine nodes.
VIII pair - vestibular cochlear nerves
(n. vestibulocochlearis) - sensitive, consists of two functionally different parts: vestibule and cochlear (see Fig. 3).
The vestibular nerve (item vestibularis) conducts impulses from the static apparatus of the vestibule and the semicircular canals of the labyrinth of the inner ear. Cochlear nerve (item cochlearis) ensures the transmission of sound stimuli from the cochlear spiral organ. Each part of the nerve has its own sensory nodes containing bipolar nerve cells: the vestibule is vestibule (ganglion vestibulare)located at the bottom of the internal auditory canal; cochlear part - cochlear knot (coiled snail knot), ganglion cochleare (ganglion spirale cochleare)that is in the snail.
The vestibule assembly is elongated; two parts are distinguished in it: top (pars superior) and bottom (pars inferior). The peripheral processes of the cells of the upper part form the following nerves:
1) elliptic saccular nerve (n. utricularis), to the cells of the elliptical sac of the vestibule of the snail;
2) anterior ampullary nerve (n. ampularis anterior), to the cells of the sensitive strips of the anterior membranous ampulla of the anterior semicircular canal;
3) lateral ampullary nerve (n. ampularis lateralis), to the lateral membranous ampulla.
From the lower part of the vestibular node, the peripheral processes of the cells are composed of spherical saccular nerve (n. saccularis) to the ear spot of the pouch and in the composition posterior ampullary nerve (n. ampularis posterior) to the posterior membranous ampulla.
The central processes of the cells of the vestibule node form vestibule (upper) spine, which exits through the internal auditory opening behind the facial and intermediate nerves and enters the brain near the exit of the facial nerve, reaching 4 vestibular nuclei in the pons: medial, lateral, superior and inferior.
From the cochlear node, the peripheral processes of its bipolar nerve cells go to the sensitive epithelial cells of the cochlear organ of the cochlea, forming in aggregate the cochlear part of the nerve. The central processes of the cells of the cochlear node form the cochlear (lower) root, which goes along with the upper root into the brain to the dorsal and ventral cochlear nuclei.
IX pair - glossopharyngeal nerves
(item glossopharyngeus) - the nerve of the third branchial arch, mixed. It innervates the mucous membrane of the posterior third of the tongue, palatine arches, pharynx and tympanic cavity, parotid salivary gland and stylopharyngeal muscle (Fig. 6, 7). The nerve contains 3 types of nerve fibers:
1) sensitive;
2) motor;
3) parasympathetic.
Figure: 6.
1 - elliptic saccular nerve; 2 - anterior ampullary nerve; 3 - posterior ampullary nerve; 4 - spherical saccular nerve; 5 - the lower branch of the vestibular nerve; 6 - the upper branch of the vestibular nerve; 7 - vestibule node; 8 - the root of the vestibular nerve; 9 - cochlear nerve
Figure: 7.
1 - tympanic nerve; 2 - knee of the facial nerve; 3 - lower salivary nucleus; 4 - double core; 5 - the core of a single path; 6 - the core of the spinal tract; 7, 11 - glossopharyngeal nerve; 8 - jugular opening; 9 - connecting branch to the ear branch of the vagus nerve; 10 - upper and lower nodes of the glossopharyngeal nerve; 12 - the vagus nerve; 13 - upper cervical node of the sympathetic trunk; 14 - sympathetic trunk; 15 - sinus branch of the glossopharyngeal nerve; 16 - internal carotid artery; 17 - common carotid artery; 18 - external carotid artery; 19 - amygdala, pharyngeal and lingual branches of the glossopharyngeal nerve (pharyngeal plexus); 20 - stylopharyngeal muscle and nerve to it from the glossopharyngeal nerve; 21 - auditory tube; 22 - tubular branch of the tympanic plexus; 23 - parotid salivary gland; 24 - ear-temporal nerve; 25 - ear node; 26 - mandibular nerve; 27 - pterygopalatine node; 28 - small stony nerve; 29 - nerve of the pterygoid canal; 30 - deep stony nerve; 31 - large stony nerve; 32 - carotid-tympanic nerves; 33 - styloid opening; 34 - tympanic cavity and tympanic plexus
Sensitive fibers- processes of afferent cells of the upper and lower nodes (ganglia superior et inferior)... Peripheral processes follow as part of the nerve to the organs, where they form receptors, the central ones go to the medulla oblongata, to the sensitive the nucleus of a solitary path (nucleus tractus solitarii).
Motor fibers start from nerve cells in common with the vagus nerve double nucleus (nucleus ambiguous) and pass as part of the nerve to the stylopharyngeal muscle.
Parasympathetic fibers originate in the autonomous parasympathetic lower salivary nucleus (nucleus salivatorius superior), which is located in the medulla oblongata.
The glossopharyngeal nerve root leaves the medulla oblongata behind the exit site of the vestibular cochlear nerve and, together with the vagus nerve, leaves the skull through the jugular foramen. In this hole, the nerve has its first extension - upper node (ganglion superior), and on exit from the hole - the second expansion - lower node (ganglion inferior).
Outside the skull, the glossopharyngeal nerve lies first between the internal carotid artery and the internal jugular vein, and then bends around the stylopharyngeal muscle behind and outside in a gentle arc and comes from the inside of the hyoid-lingual muscle to the root of the tongue, dividing into terminal branches.
Branches of the glossopharyngeal nerve.
1. The tympanic nerve (item tympanicus) branches off from the lower node and passes through the tympanic tubule into the tympanic cavity, where it forms, together with the carotid-tympanic nerves tympanic plexus (plexus tympanicus). The tympanic plexus innervates the mucous membrane of the tympanic cavity and auditory tube. The tympanic nerve leaves the tympanic cavity through its top wall as petrous nerve (n. petrosus minor) and goes to the ear node Preganglionic parasympathetic secretory fibers, suitable as part of the small stony nerve, are interrupted in the ear node, and the postganglionic secretory fibers enter the auricular-temporal nerve and reach the parotid salivary gland in its composition.
2. A branch of the stylopharyngeal muscle (r. t. stylopharyngei) goes to the muscle of the same name and the mucous membrane of the pharynx.
3. Sinus branch (r. Sinus carotid), sensitive, branches in the sleepy glomus.
4. Almond branches (rr. tonsillares) are directed to the mucous membrane of the palatine tonsil and arches.
5. The pharyngeal branches (rr. Pharyngei) (3-4 in number) approach the pharynx and, together with the pharyngeal branches of the vagus nerve and the sympathetic trunk, form on the outer surface of the pharynx pharyngeal plexus (plexus pharyngealis)... Branches extend from it to the muscles of the pharynx and to the mucous membrane, which, in turn, form intramural nerve plexuses.
6. Lingual branches (rr. Linguales) - terminal branches of the glossopharyngeal nerve: contain sensitive taste fibers to the mucous membrane of the posterior third of the tongue.
Human Anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin