Antipyretics for children are prescribed by a pediatrician. But there are emergency situations for fever when the child needs to be given medicine immediately. Then the parents take responsibility and use antipyretic drugs. What is allowed to give to infants? How can you bring down the temperature in older children? What medicines are the safest?
cranial nerves 6) medulla oblongata
Grade 8 BiologyOption 3
Level A
1. Specify the central, main part of the cell?
1) ribosomes; 2) cytoplasm; 3) core.
2. Which of these processes occurs first in cell division?
1) nuclear fission; 2) self-doubling of chromosomes;
3) doubling of the cell center.
3. What tissue forms nails and hair?
1) epithelial; 2) connecting; 3) muscular.
4. What is the name of the liquid part of the blood?
1) lymph; 2) plasma; 3) water.
5. What soluble plasma protein is involved in clotting?
1) hemoglobin; 2) fibrin; 3) fibrinogen.
6. What structural features 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 an indicator of the development of the heart?
1) an increase in the mass of the heart; 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) semilunar valves are open, leaflets are closed;
2) semilunar valves are closed, leaflets are open;
3) all valves are open.
10. Which human bones are most developed in connection with physical
labor?
1) bones of the hand; 2) bones of the forearm; 3) femur.
11. What tissue do skeletal muscles consist of?
1) smooth muscle; 2) striated; 3) connecting.
12. What physiological processes occur in muscle cells
fabrics?
1) supply of O2 and release of CO2;
2) entry of organic substances and O2 into the cell;
3) intake of organic substances and O2, oxidation and decay, removal
CO2.
14. Specify 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 hemispheres of the brain divided into?
2. What vitamin should be given to a patient with scurvy?
3. How many semicircular canals does the organ of balance have?
4. How many cervical vertebrae does a person have?
5. How many pairs of cranial nerves does a person have?
Level C:
1. Do mental abilities depend on the mass of the brain?
2. Why is it said that the eye looks and the brain sees?
1) Central
B) Nerve nodes 2) Peripheral
B) spinal cord
D) brain
D) nerve endings
E) cranial nerves
What structures are included in the human peripheral nervous system? Choose three correct answers from six and write down the numbers under which they are indicated. 1)spinal nerves 2) forebrain 3) nerve nodes 4) spinal cord 5) cranial nerves 6) medulla oblongata
In spiders and echinoderms, digestion is: a. Intracavitary, b. intracellular, c. Outdoor, Mr. There is no correct answer.Complication digestive system along the way: a. Complications of the digestive glands, b. Its elongation, c. Suction surface increase, g. All of the above.
Substances that speed up all reactions in the body are called: a. Digestive juices b. vitamins, c. Metabolic products, Enzymes.
The nervous system of the ladder type is developed in: a. Annelids, b. Hydra, in Arthropods, Planaria.
In birds, compared with reptiles, the most developed part of the brain: a. Interbrain, c. Large hemispheres, c. Cranial nerves, d. All of the above.
In what organ of the mammalian circulatory system is blood saturated with oxygen? A. In the veins of the small circle, b. in the capillaries great circle, V. In the veins of the large circle, d. In the capillaries of the small circle.
In which part of the digestive system are nutrients absorbed? A. In the large intestine, b. In the stomach, in IN small intestine, g. In the rectum.
Help please, I'm just at home schooling, teachers rarely come because they are busy.
TWELVE PAIRS OF CRANIONERVOUS
Compiled by Academician of the Russian Academy of Medical Sciences, Doctor of Medical Sciences, Professor of the Department of Normal Anatomy of the Moscow State Medical University, Pavlova Margarita Mikhailovna
Twelve pairs of cranial nerves:
I pair of cranial nerves - n. olfactorius - olfactory nerve;
II pair of cranial nerves - n. opticus - optic nerve;
III pair of cranial nerves - n. oculomotorius - oculomotor nerve;
IV pair of cranial nerves - n. trochlearis - trochlear nerve;
V pair of cranial nerves - n. trigeminus - trigeminal nerve;
VI pair of cranial nerves - n. abducens - abducens nerve;
VII pair of cranial nerves - n. facialis - facial nerve;
VIII pair of cranial nerves - n. vestibulocochlearis - static auditory nerve;
IX pair of cranial nerves - n. glossopharyngeus - glossopharyngeal nerve;
X pair of cranial nerves - n. vagus - vagus nerve;
XI pair of cranial nerves - n. accessorius - accessory nerve;
XII pair of cranial nerves - n. hypoglossus - hypoglossal nerve.
I a pair of cranial nerves n . olfactorius - olfactory nerve , sensitive. It develops from the olfactory brain - an outgrowth of the forebrain, therefore there are no nodes. From the nasal cavity (from the receptors) - the posterior sections of the superior and middle turbinates → 18-20 threads (filae olfactoriae) - these are the central processes of the olfactory cells → regio olfactoria (olfactory region) → lamina cribrosa ossis ethmoidalis → bulbus olfactorius (olfactory bulb) → tractus olfactorius (tract) → trigonum olfactorium (olfactory triangle).
In pathology: decrease, increase, absence or perversion (olfactory hallucinations) of smell.
II a pair of cranial nerves n . opticus - optic nerve , by function - sensitive. It is an outgrowth of the diencephalon, connected with the midbrain. Has no nodes. It starts from the rods and cones on the retina → canalis opticus → chiasma optici (optic chiasm), at the level of sella thurcica in the sulcus chiasmatis of the sphenoid bone. Only the medial bundles cross → tractus opticus → corpus geniculatum laterale → pulvinar thalami → superior tubercles of the quadrigemina. It ends in the occipital lobe - sulcus calcarinus.
In case of damage, the fields of view of one's own or someone else's eye fall out:
When defeated optic nerve: blindness, decreased vision, visual hallucinations.
III a pair of cranial nerves n . oculomotorius - oculomotor nerve . By function - mixed, but mainly motor for the muscles of the eye. It has motor and parasympathetic nuclei - (nucleus accessorius). It leaves the brain along the medial edge of the brain stem → fissura orbitalis superior → into the orbit
|
ramus superior (to m. rectus superior, to m. levator palpebrae superior) |
ramus inferior (to m. rectus inferior et medialis and to m. obliquus inferior) |
Root → to ganglion celiare with parasympathetic fibers - for m. sphincter pupillae and m. ciliaris.
The triad of symptoms in the defeat of n. oculomotorius:
1) Ptos (drooping of the upper eyelid) - the defeat of m. levator palpebrae superior.
2) Divergent strabismus (innervation of the VI pair of cranial nerves prevails) → stropismus divergens.
3) Pupil dilation (damage to m. sphincter pupillae). The dilator (mydrias) prevails.
The superior, inferior, and medial rectus muscles are innervated by the third cranial nerve.
The external rectus muscle of the eye is the VI pair of cranial nerves.
The superior oblique muscle of the eye is the 4th pair of cranial nerves.
The inferior oblique muscle of the eye is the 3rd pair of cranial nerves.
The muscle that lifts the upper eyelid (m. Levator palpebrae superior - III pair of cranial nerves (antagonist of the VII pair of cranial nerves for m. Orbicularis oculi).
M. sphincter pupillae (pupil constrictor) - III pair of cranial nerves (parasympathetic branch as part of n. oculomotorius).
M. dilatator pupillae (the muscle that dilates the pupil) is the antagonist of the constrictor. Innervated by the sympathetic nervous system.
IV a pair of cranial nerves n . trochlearis - trochlear nerve. By function - motor. It emerges from the superior medullary velum, goes around the brain stem → fissura orbitalis superior, enters the orbit. Innervates the superior oblique muscle of the eye - m. obliquus oculi superior. With pathology, double vision due to the oblique standing of the eyeballs, as well as a symptom of the impossible descent from the stairs.
V a pair of cranial nerves n . trigeminus - trigeminal nerve. Functionally, it is a mixed nerve. Contains motor, sensory and parasympathetic fibers. Innervates all chewing muscles, skin of the face, teeth, glands of the oral cavity.
1) one motor and three sensory nuclei;
2) sensory and motor roots;
3) trigeminal node on the sensitive root (ganglion trigemenale);
5) three main branches: ophthalmic nerve, maxillary nerve, mandibular nerve.
Cells of the trigeminal node (ganglion trigemenale) have one process, dividing into two branches: central and peripheral.
Central neurites form a sensitive root - radix sensoria, enter the brainstem → sensitive nerve nuclei: the pontine nucleus (nucleus pontis nervi trigemini), the nucleus of the spinal tract (nucleus spinalis nervi trigemini) - the hindbrain, the nucleus of the mesencephalic tract - nucleus mesencephalicus nervi trigemini - middle brain.
The peripheral processes are part of the main branches of the trigeminal nerve.
Motor nerve fibers originate in the motor nucleus of the nerve - the nucleus motorius nervi trigemini (hindbrain). Coming out of the brain, they form a motor root - radix motoria.
Autonomic ganglions are connected with the main branches of the trigeminal nerve.
1) Ciliary node - with the optic nerve;
2) Pterygopalatine node - with the maxillary nerve;
3) Ear and submandibular - with the mandibular nerve.
Each branch of the trigeminal nerve (ophthalmic, maxillary, mandibular) gives off:
1) branch to the dura mater;
2) branches to the mucous membrane of the oral cavity, nose, to the paranasal (paranasal, accessory) sinuses;
3) to the organs of the lacrimal gland, salivary glands, teeth, eyeball.
I. N. ophthalmicus- ophthalmic nerve
Functionally sensitive. It innervates the skin of the forehead, the lacrimal gland, part of the temporal and parietal region, the upper eyelid, the back of the nose (upper third of the face). Passes through fissura orbitalis superior.
Branches: lacrimal nerve (n. lacrimalis), frontal nerve (n. frontalis), nasociliary nerve (n. nasociliaris).
N. lacrimalis innervates the lacrimal gland, the skin of the upper eyelid, and the outer canthus of the eye.
n. supraorbitalis (supraorbital nerve) through incisura supraorbitalis - to the skin of the forehead;
n. supratrochlearis (supratrochlearis nerve) - for the skin of the upper eyelid and medial canthus.
N. nasociliaris. Its terminal branch is n. infratrochlearis (for the lacrimal sac, medial angle of the eye, conjunctiva).
nn. ciliares longi (long ciliary branches) - to the eyeball,
n. ethmoidalis posterior (posterior ethmoid nerve) - to the paranasal sinuses (sphenoid, ethmoid).
n. ethmoidalis anterior - to the frontal sinus, nasal cavity: rr. nasales medialis et lateralis, r. nasalis externus.
Vegetative node of the first branch of the V pair of cranial nerves - ciliary node - ganglion ciliare. It lies on the outer surface of the optic nerve (in the orbit) between the posterior and middle thirds. It comes from three sources:
a) sensitive root - radix nasociliaris (from n. nasociliaris);
b) parasympathetic - from n. oculomotorius;
c) sympathetic - radix sympathicus from plexus sympathicus a. ophthalmica.
II. N. maxillaris- maxillary nerve- for the middle third of the face, the mucous membrane of the nasal cavity and mouth, upper lip. Enters through the foramen rotundum.
r. meningeus (to dura mater) in the pterygopalatine fossa;
nodal branches - rr. ganglionares - sensitive branches to ganglion pterygopalatinum;
zygomatic nerve (n. zygomaticus);
infraorbital nerve (n. infraorbitalis).
The vegetative node of the second branch of the V pair of cranial nerves is the pterygopalatine node - ganglion pterygopalatinum. It comes from three sources:
a) sensitive root - nn. pterygopalatini;
b) parasympathetic root - n. petrosus major (7th pair of cranial nerves + n. intermedius);
c) sympathetic root - n. petrosus profundus (from plexus caroticus internus).
Depart from ganglion pterygopalatinum: rr. orbitales (orbital branches), rr. nasales posteriores superiores (posterior superior nasal branches), nn. palatine (palatine branches).
Rr. orbitalis through fissura orbitalis inferior → into the orbit, then from n. ethmoidalis posterior → to the ethmoid labyrinth and sinus sphenoidalis.
Rr. nasales posteriores → through foramen sphenopalatinum → into the nasal cavity and are divided into: rr. nasales posteriores superiores lateralis and rr. nasales posteriores superiores medialis.
Nn. palatini → through canalis palatinus and are divided into: n. palatinus major (through foramen palatinum major), nn. palatini minores (through foramina palatina minora), rr. nasales posteriores inferiores (for the posterior parts of the nasal cavity).
N. zygomaticus (zygomatic nerve) → exits through the foramen zygomaticoorbitale and divides into: r. zygomaticofacialis and r. zigomaticotemporalis (exit through the holes of the same name). It enters the orbit from the pterygopalatine fossa through the fissura orbitalis inferior.
N. infraorbitalis (infraorbital nerve). From the pterygopalatine fossa → fissura orbitalis inferior → sulcus infraorbitalis → foramen infraorbitale.
nn. alveolares superiores posteriores innervate the posterior third of the teeth of the upper jaw. Pass through foramina alveolaria posteriora to tuber maxillae → canalis alveolaris, form a plexus;
nn. alveolares superiores medii (1-2 stems). They depart within the orbit or pterygopalatine fossa. Innervate the middle third of the teeth of the teeth of the upper jaw;
nn. alveolares superiores anteriores (1-3 stems) - for the front upper teeth of the upper jaw.
From n. infraorbitalis depart:
nn. alveolares superiores (for teeth);
rr. palpebrales inferiores (for eyelids);
rr. nasales externi;
rr. nasales interni;
rr. labiales superiores - for the upper lip.
III. N. mandibularis -mandibular nerve. Mixed nerve. Its branches:
a) r. meningeus - with a. meninfea media passes through the foramen spinosum. The nerve is sensitive to the dura mater.
b) n. massetericus - for the muscle of the same name;
c) nn. temporales profundi - for the temporal muscle;
d) n. pterygoideus lateralis - for the muscle of the same name;
e) n. pterygoideus medialis - for the muscle of the same name;
n. pterygoideus medialis: n. tensor tympani, n. tensor veli palatini - for the muscles of the same name.
e) n. buccalis, sensitive (buccal nerve) - for the buccal mucosa.
g) n. auriculotemporalis - ear-temporal nerve, sensitive, passes anterior to the external auditory canal, perforates the glandula parotis, goes to the temple area: rr. auricularis, rr. parotidei, n. meatus acusticus externus, nn. auriculares anteriores.
h) n. lingualis (lingual), sensitive. It is joined by chorda tympani (drum string) → continued n. intermediate. Contains secretory fibers to the submandibular and sublingual nerve nodes + taste - to the papillae of the tongue.
Branches n. lingualis: rr. isthmi faucium, n. sublingualis, rr. linguales.
Ganglion submandibulare (submandibular node) is formed from three sources:
a) nn. linguales (sensitive, from n. trigeminus);
b) chorda tympani - parasympathetic nerve from the VII pair of cranial nerves (n. intermedius);
c) plexus sympaticus a facialis (sympathetic).
Vegetative node of the third branch n. trigeminus innervates the submandibular and sublingual salivary glands.
Ganglion oticum (ear node) - vegetative node n. mandibularis. Lies under the foramen ovale, on the medial surface n. mandibularis. It comes from three sources:
a) n. mandibularis - sensitive branches (n. auriculotemporalis, n. meningeus);
b) n. petrosus minor - parasympathetic nerve - terminal branch of n. tympanicus (IX pair of cranial nerves);
c) plexus sympathicus a. meningea media.
Ganglion oticum innervates the salivary gland through n. auriculotemporalis.
i) n. alveolaris inferior (lower alveolar nerve) - mixed. Predominantly sensitive to the teeth of the lower jaw, forming a plexus. Leaves the channel through the foramen mentale. Enters the canal through the foramen mandibulare of the lower jaw.
n. mylohyoideus (for venter anterior m. digastrici and m. mylohyoideus);
rr. dentales et gingivales - for the gums and teeth of the lower jaw;
n. mentalis - mental nerve - continuation of the trunk n. alveolaris inferior. It leaves the canalis mandibularis through the foramen mentale.
Its branches:
rr. mentales (for the skin of the chin);
rr. labiales inferiores (for the skin and mucous membrane of the lower lip).
VI a pair of cranial nerves n . abducens - abducens nerve. By function - motor. Innervates the external rectus muscle of the eye - m. rectus oculi lateralis. In case of damage, the internal rectus muscle of the eye (III pair of cranial nerves) prevails - there will be convergent strabismus (stropismus convergens). The core is located in the bridge. It enters the orbit through the fissura orbitalis superior together with III, IV pairs of cranial nerves + the first branch of the V pair of cranial nerves.
VII a pair of cranial nerves n . facialis - facial nerve The nerve is mixed, predominantly motor for the mimic muscles of the face.
Has three cores in the bridge:
From linea trigeminofacialis with the VIII pair (n. vestibulocochlearis) passes into porus acusticus internus → canalis facialis.
There are three directions of the nerve in the canal: 
Horizontally (in the frontal plane), then sagitally, then vertically. It exits the skull through the foramen stylomastoideum. Between the first and second parts, a bend is formed in the form of a knee - genu n. facialis with the formation of ganglion geniculi (knee) as a result of the addition of n. intermedius, therefore, below the knee - branches with a vegetative function.
With pathology: open eye on the side of the lesion and the distortion of the face to the healthy side, impaired salivation, lack of taste for sweets, the nasolabial fold is smoothed, the corner of the mouth is lowered, dryness of the eyeball.
Branches in the pyramid of the temporal bone:
1) n. stapedius - to m.stapedius (“stapes” - stirrup). motor nerve.
2) n. petrosus major, secretory nerve, autonomic. Departs from genu n.facialis. It leaves the pyramid through the hiatus canalis n. petrosi majoris → sulcus n. petrosi majores → canalis pterygoideus together with the sympathetic nerve - n. petrosus profundus from plexus caroticus internus. Both nerves form n. canalis pterygoidei → ganglion pterygopalatinum: rr. nasales posteriores, nn. palatini.
Part of the fibers through n. zygomaticus (from n.maxillaris) through connections with n. lacrimalis reaches the lacrimal gland.
Branches n. facialis, which form in the glandula parotis plexus parotideus and the great crow's foot - pes anserina major.
3) Chorda tympani - from the vertical part of the nerve. The drum string is a vegetative, parasympathetic nerve.
N. intermedius (intermediate nerve), mixed. Contains:
1) taste fibers - to the sensitive nucleus - nucleus tractus solitarii
2) efferent (secretory, parasympathetic) fibers from the autonomic nucleus - nucleus solivatorius superior.
N. intermedius leaves the brain between n. facialis and n. vestibulocochlearis, joins the VII pair of cranial nerves (portio intermedia n. Facialis). Then it goes into chorda tympani and n. petrosus major.
Sensory fibers originate from ganglion geniculi cells. The central fibers of these cells → to the nucleus tractus solitarii.
Chorda tympani conducts taste sensitivity of the anterior sections of the tongue and soft palate.
Secretory parasympathetic fibers from n. intermedius start from the nucleus solivatorius superior → along chorda tympani → sublingual and submandibular salivary glands (through ganglion submandibulare and along n. petrosus major through ganglion pterygopalatinum - to the lacrimal gland, to the glands of the mucous membrane of the nasal cavity and palate).
The lacrimal gland receives secretory fibers from n. intermedius through n. petrosus major, ganglion pterygopalatinum + anastomosis of the second branch of the V pair of cranial nerves (n. maxillaris with n. lacrimalis).
N. intermedius innervates all glands of the face except glandula parotis, which receives secretory fibers from n. glossopharyngeus (IX pairs of cranial nerves).
VIII a pair of cranial nerves n . vestibulocochlearis - vestibulocochlear nerve n . statoacousticus ). The nerve is sensitive. The fibers come from the organ of hearing and balance. It consists of two parts: pars vestibularis (balance) and pars cochlearis (hearing).
The node pars vestibularis - ganglion vestibulare lies at the bottom of the internal auditory meatus. The node pars cochlearis - ganglion spirale lies in the cochlea.
Peripheral processes of cells end in the perceiving devices of the labyrinth. The central processes - porus acusticus internus - into the nuclei: pars vestibularis (4 nuclei) and pars cochlearis (2 nuclei).
With pathology - impaired hearing and balance.
IX a pair of cranial nerves n . glossopharyngeus - Glossopharyngeal nerve. The function is mixed. Contains: a) afferent (sensory) fibers from the pharynx, tympanic cavity, posterior third of the tongue, tonsils, palatine arches;
b) efferent (motor) fibers innervating m. stylopharyngeus;
c) efferent (secretory) parasympathetic fibers for glandula parotis.
It has three cores:
1) nucleus tractus solitarii, which receives the central processes of the ganglion superior et inferior;
2) vegetative nucleus (parasympathetic) - nucleus solivatorius inferior (lower salivary). Has cells scattered in the formatio reticularis;
3) motor nucleus, common with n. vagus - nucleus ambiguus.
It leaves the skull with the X pair of cranial nerves through the foramen jugulare. Within the hole, a node is formed - ganglion superior, and under it - ganglion inferior (the lower surface of the pyramid of the temporal bone).
1) N. tympanicus (from ganglion inferior → cavum tympani → plexus tympanicus with plexus sympaticus a. crotis interna (for the auditory tube and tympanic cavity) → n. petrosus minor (exits through a hole on the upper wall of the tympanic cavity) → sulcus n. petrosi minores → ganglion oticum (parasympathetic fibers for the parotid salivary gland as part of n. auriculotemporalis (from the third branch of the fifth pair of cranial nerves).
2) R. m. stylopharyngei - to the pharyngeal muscle of the same name;
3) Rr. tonsillares - to the arches, palatine tonsils;
4) Rr. pharyngei - to the pharyngeal plexus.
X a pair of cranial nerves n . vagus - nervus vagus. Mixed, predominantly parasympathetic.
1) Sensitive fibers come from receptors internal organs and vessels, from dura mater, meatus acusticus externus to the sensitive nucleus - nucleus tractus solitarii.
2) Motor (efferent) fibers - for the hepatic-striated muscles of the pharynx, soft palate, larynx - from the motor nucleus - the nucleus ambiguus.
3) Efferent (parasympathetic) fibers - from the autonomic nucleus - nucleus dorsalis n. vagi - to the heart muscle (bradycardia), to the smooth muscles of the vessels (expand).
As part of n. vagus goes n. depressor - regulates blood pressure.
Parasympathetic fibers narrow the bronchi, trachea, innervate the esophagus, stomach, intestines to the colon sigmoideum (increase peristalsis), liver, pancreas, kidneys (secretory fibers).
It emerges from the medulla oblongata. In the foramen jugulare it forms a ganglion inferior.
Peripheral processes of cells are part of the sensitive branches from the receptors of the viscera and blood vessels - meatus acusticus externus. The central processes end in the nucleus tractus solitarii.
A. Head part:
r. memningeus - to the dura mater;
r. auricularis - to the external auditory canal.
B. Neck:
rr. pharyngei → pharyngeal plexus with cranial nerve IX + truncus sympathicus;
n. laryngeus superior: sensory branches for the root of the tongue, motor branches for m. cricothyreoideus anterior (the remaining muscles of the larynx are innervated by n. laryngeus inferior from n. laryngeus recurrens);
rr. cardiaci superiores (for the heart).
B. Chest:
n. laryngeus recurrents;
r. cardiacus inferior (from n. laryngeus recurrens);
rr. bronchiales et trachleares - to the trachea, bronchi;
rr. esophagei - to the esophagus.
D. Abdomen:
truncus vagalis anterior (together with fibers of the sympathetic nervous system);
truncus vagalis posterior;
plexus gastricus anterior;
plexus gastricus posterior → rr. celiaci.
XI a pair of cranial nerves n . accessorius - Accessory nerve. Motor for m. sternocleidomastoideus and m. trapezius. It has two motor nuclei in medulla oblongata and medulla spinalis → nucleus ambiguus + nucleus spinalis.
It has two parts: head (central), spinal.
XI pair - split off part of n. vagus. The head part connects to the spinal portion and exits the skull through the foramen jugulare along with the IX and X pairs of cranial nerves.
The spinal portion is formed between the roots of the spinal nerves (C 2 -C 5) of the upper cervical nerves. It enters the cranial cavity through the foramen occipitale magnum.
With the defeat of the XI pair of cranial nerves - torticollis (torticolis) - head tilt to the healthy side with a turn in the direction of the lesion.
XII a pair of cranial nerves n . hypoglossus - hypoglossal nerve. Motor, mainly for the muscles of the tongue and neck muscles. It contains sympathetic fibers from the superior cervical sympathetic ganglion. There is a connection with n. lingualis and with the lower node n. vagus. Somatic motor nucleus in trigonum nervi hypoglossi of the rhomboid fossa → formation reticularis, descending through the medulla oblongata. On the basis of the brain - between the olive and the pyramid → canalis n. hypoglossy. Forms the upper wall of the Pirogov triangle - arcus n. hypoglossi.
The branch of the XII pair connects to the cervical plexus, forming ansa cervicalis (innervates the muscles below the os hyoideum) - m. sternohyoideus, m. sternothyreoidus, m. thyreohyoideus and m. onohyoideus.
With the defeat of n. hypoglossus protruding tongue deviates towards the lesion.
7. VII pair of cranial nerves - facial nerve
He is mixed. The motor pathway of the nerve is two-neuron. The central neuron is located in the cerebral cortex, in the lower third of the precentral gyrus. Axons of central neurons head towards the nucleus facial nerve, located on the opposite side in the bridge of the brain, where the peripheral neurons of the motor pathway are located. The axons of these neurons make up the facial nerve root. The facial nerve, passing through the internal auditory opening, is sent to the pyramid of the temporal bone, located in the facial canal. Next, the nerve exits the temporal bone through the stylomastoid foramen, entering the parotid salivary gland. In the thickness of the salivary gland, the nerve divides into five branches, forming the parotid plexus.
The motor fibers of the VII pair of cranial nerves innervate the mimic muscles of the face, stapedius muscle, muscles auricle, skull, subcutaneous muscle of the neck, digastric muscle (its posterior abdomen). In the facial canal of the pyramid of the temporal bone, three branches depart from the facial nerve: a large stony nerve, a stapedial nerve, and a tympanic string.
The large stony nerve passes through the pterygopalatine canal and ends at the pterygopalatine ganglion. This nerve innervates the lacrimal gland by forming an anastomosis with the lacrimal nerve after interruption in the pterygopalatine ganglion. The large stony nerve contains parasympathetic fibers. The stapedial nerve innervates the stapedial muscle, causing its tension, which creates conditions for the formation of better audibility.
The drum string innervates the anterior 2/3 of the tongue, being responsible for the transmission of impulses with a variety of taste stimuli. In addition, the drum string provides parasympathetic innervation of the sublingual and submandibular salivary glands.
Damage symptoms. If the motor fibers are damaged, peripheral paralysis of the facial muscles develops on the side of the lesion, which is manifested by asymmetry of the face: half of the face on the side of the nerve lesion becomes motionless, mask-like, the frontal and nasolabial folds are smoothed out, the eye on the affected side does not close, the palpebral fissure expands, the corner of the mouth is lowered down .
Bell's phenomenon is noted - an upward turn of the eyeball when trying to close the eye on the side of the lesion. There is paralytic lacrimation due to the absence of blinking. Isolated paralysis of the mimic muscles of the face is characteristic of damage to the motor nucleus of the facial nerve. In the case of joining the lesion of the radicular fibers to the clinical symptoms, Miyyar-Gubler syndrome is added (central paralysis of the extremities on the side opposite to the lesion).
With damage to 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 lesion of the auditory and trigeminal nerves. This pathology occurs with inflammation of the cerebellopontine angle (arachnoiditis), acoustic neuroma. The addition of hyperacusis and a violation of taste indicate damage to the nerve before the large stony nerve leaves it in the facial canal of the temporal bone pyramid.
Damage to the nerve above the tympanic string, but below the origin of the stapedial nerve, is characterized by a taste disorder, lacrimation.
Paralysis of the mimic muscles in combination with lacrimation occurs in case of damage to the facial nerve below the discharge of the tympanic string. Only the cortical-nuclear pathway may be affected. Clinically observed paralysis of the muscles of the lower half of the face on the opposite side. Often paralysis is accompanied by hemiplegia or hemiparesis on the side of the lesion.
From the book Nervous Diseases author M. V. Drozdov From the book Nervous Diseases author M. V. Drozdov From the book Nervous Diseases author M. V. Drozdov From the book Nervous Diseases author M. V. Drozdov From the book Nervous Diseases author M. V. Drozdov author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. Drozdov From the book Nervous Diseases: Lecture Notes author A. A. DrozdovVII pair, n. facialis - motor nerve. Kernel n. facialis is located quite deep in the lower department pons varolii, on its border with the medulla oblongata (om. Fig. 23,24 and 50). The fibers emanating from the cells of the nucleus rise dorsally to the bottom of the rhomboid fossa and go around the nucleus n from above. abducentis (VI nerve), forming the so-called knee (internal) of the facial nerve.
Further, the fibers go down and exit as a root on the base between the pons and the medulla oblongata (see Fig. 22), lateral to the olive, in the pontocerebellar angle (together with n. intermedius Wrisbergi and n. acusticus), following in the direction of the porus acusticus internus. At the base of the meatus acusticus of the facial and vrisberg nerves depart from the auditory and enter the canalis facialis Fallopii (see Fig. 27). Here, in the pyramid of the temporal bone, the VII nerve again forms the knee (external) and finally exits the skull through the foramen stylo-mastoideum, dividing into a number of terminal branches ("crow's foot", pes anserinus). N. facialis is the motor nerve of the facial muscles and innervates all mimic muscles (except m. levator palpebrae superioris - III nerve), m. digastricus (hind belly), m. stylo-hyoideus and finally m. stapedius and m. platysma myoides on the neck. For a considerable distance, the companion of the facial nerve is n. intermedius Wrisbergi, also called the XIII cranial nerve.
This is a mixed nerve, having centripetal sensitive, more precisely - taste, and centrifugal secretory salivary fibers. In its meaning, it is largely identical to the glossopharyngeal nerve, with which it has common nuclei. Sensitive taste fibers start from the cells of the ganglion geniculi, located in the genu canalis facialis, in the temporal. bones. They go to the periphery along with n. facialis to the fallopian canal and leave the latter as part of the chorda tympani (Fig. 28); later they enter the trigeminal nerve system and through r. lingualis n.. trigemini reach the tongue, supplying its anterior two-thirds with taste endings (the posterior third is innervated from the glossopharyngeal nerve). Axons of cells n. intermedii from ganglion geniculi together with n. facialis enter the brain stem in the ponto-cerebellar angle and end in common with the IXth nerve in the “gustatory” nucleus - nucleus tractus solitarius 16.
Secretory salivary fibers of the XIII nerve come from the nucleus salivatorius common with the IX nerve and pass together with n. facialis, leaving the canalis facialis as part of the same chordae tympani; they innervate submandibular and sublingual salivary glands(glandula submaxillaris and glandula sublingualis). Except n. Wrisbergi, for a certain extent, accompany the facial nerve and secretory lacrimal fibers, starting from a special secretory nucleus located close to the nucleus of the seventh nerve. Together with n. facialis, these fibers enter the falliopean canal, which they soon leave as part of n. petrosus superficial-is major. Further tear fibers enter the trigeminal nerve system and through n. lacrimalis(V nerve) reach the lacrimal glands. With the defeat of these fibers, there is no lacrimation and dryness of the eye is observed.
Slightly below the departure of n. petrosus superficialis major are separated from. facial nerve and leave the fallopian canal and fibers n. stapedii. With the defeat of the muscle of the same name innervated by him, hyperakusis is observed (unpleasant, increased perception of sound, especially low tones).
Below the named two branches leaves the bone canal and separates from the facial nerve chorda tympa-ni- continuation of n. Wrisbergi with its taste fibers for the anterior two-thirds of the tongue and salivary for the submandibular and sublingual glands (see Fig. 28).
Damage to the VII nerve causes peripheral paralysis of the mimic muscles (prosopoplegia). Even with a simple examination, a sharp asymmetry of the face is striking (Fig. 29). The affected side is mask-like, the folds of the forehead and the nasolabial fold are smoothed here, the main gap is wider, the corner of the mouth is lowered. When wrinkling the forehead on the side of the paralysis, no folds are formed (m. frontalis is affected); when squinting, the palpebral fissure does not close (lagophtalmus) due to the weakness of m. orbicularis oculi. At the same time, the discharge of the eyeball upwards (Bell's phenomenon) is visible, and there is more on the side of the lesion than on the healthy one 17 . With lagophthalmos, there is usually (for an exception, see below) increased lacrimation. When showing teeth, the corner of the mouth on the affected side is not pulled back (m. risorius), m. platysma myoides on the neck. Whistling is impossible, speech is somewhat difficult (m. orbicularis oris). As with any peripheral paralysis, there is a rebirth reaction, the superciliary reflex is lost or weakened(and corneal). The height of the lesion of the facial nerve should be determined depending on the symptoms accompanying the described picture.
When the nucleus or fibers inside the brain stem are damaged (see Fig. 28), the lesion of the facial nerve is accompanied by central paralysis or paresis of the extremities of the opposite side (alternating Miyar-Gubler syndrome), sometimes with the addition of a lesion n. abducentis (Fauville's syndrome).
Root damage n. facialis at the site of its exit from the brain stem is usually combined with a lesion of n. acustici (deafness) and other symptoms of damage to the cerebellopontine angle (see Fig. 22). Paralysis of the facial nerve in these cases is not accompanied by lacrimation (dry eye), there is a violation of taste in the anterior two-thirds of the tongue, and dryness in the mouth may be felt. Hyperakusis is not observed due to the combined lesion of the VIII nerve.
With processes in the area of the bone canal up to genu n. facialis, i.e. above the departure of n. petrosi superficial is majoris, along with paralysis, dry eyes, disorders of taste and salivation are also noted(see fig. 28); on the part of hearing, hyperakusis is observed here(damage to the fibers of n. stapedii).
With a lesion in the bone canal below the discharge of n. petrosi, the same disorders of taste, salivation and hyperakusis are observed along with paralysis, but instead of dryness of the eye, increased lacrimation occurs.
In case of damage to the facial nerve in the bone canal below departures n. stapedii and above chordae tympan i (see Fig. 28) paralysis, lacrimation, disorders of taste and salivation.
Finally, if the nerve is damaged in the bone below the origin of the chordae tympani or already after its exit from the skull through the foramen stylo-mastoideum observed only paralysis with lachrymation without those accompanying symptoms, which were discussed at higher lesions.
The most frequent are the latter cases with peripheral localization of the process, and the paralysis is usually unilateral. Cases of diplegiae facialis are quite rare. It should be noted that with peripheral paralysis of the facial nerve, especially at the onset of the disease, pain in the face, in the ear and in its circumference (especially often in the mastoid process) is very often observed. This is due to the presence on the face of rather intimate connections (anastomoses) with the branches of the trigeminal nerve, the possible passage of sensory fibers of the 5th nerve into the canalis facialis (chorda tympani - canalis Fallopii - n. petrosis superficialis major), the simultaneous involvement of the facial nerve and the root of the trigeminal nerve or its node during processes based on the brain (see Fig. 22).
Central paralysis(paresis) of the facial muscles are observed, as a rule, in combination with hemiplegia. Isolated lesions of the facial muscles of the central type are rare and are sometimes observed with damage to the frontal lobe or only the lower part of the anterior central gyrus. It is clear that the central paresis of the facial muscles is the result of a supranuclear lesion of the tractus cortico-bulbaris in any of its parts (cerebral cortex, corona radiata, capsula interna, cerebral peduncles, pons). With central paralysis, the upper facial muscles (m. frontalis, m. orbicularis oculi) hardly suffer, and only the lower (oral) muscles are affected. This is explained by the fact that the upper cell group of the VII nerve nucleus has a bilateral cortical innervation, in contrast to the lower one, to the cells of which the fibers of the central nerves (tractus cortico-bulbaris) approach, mainly only from the opposite hemisphere. With central paralysis of the facial muscles, unlike the peripheral one, there will be no reaction of degeneration; the superciliary reflex is preserved and even enhanced.
To phenomena irritation in areas of the facial muscles include various kinds of tics (a manifestation of neurosis or organic disease), contractures that may be a consequence of peripheral paralysis of the VII nerve, localized spasm, other clonic and tonic convulsions (cortical or subcortical hyperkinesis).
Anatomy. The facial nerve originates in the nucleus of the bridge, located on the border with the medulla oblongata, posterior and outward from the nucleus of the abducens nerve. Its central part innervates the mimic muscles of the lower part of the same half of the face and is connected only with the opposite hemisphere of the brain. The dorsal part innervates the muscles of the upper parts of the face with both hemispheres of the brain.
The fibers emerging from the nucleus loop around the nucleus of the abducens nerve, forming the inner knee of the FN. Then they go outward and ventrally to the cerebellar pontine angle, in the region of which they exit the substance of the brain. Further, the facial nerve enters through the internal auditory opening of the petrous part (pyramid) of the temporal bone into the internal auditory meatus, and from it penetrates into the canal of the facial nerve. In the initial part of this canal, the intermediate nerve joins it, which in its composition contains sensitive (gustatory) and autonomic (secretory) fibers. Sensitive fibers are associated with the nucleus, and secretory - with the upper salivary nucleus, common nuclei with the glossopharyngeal nerve. In the bone canal, the facial nerve makes a bend (external knee of the FN). In this place, the facial nerve thickens due to the geniculate node, which belongs to the sensitive part of the intermediate nerve. After leaving the canal, the LN passes through the parotid gland and divides into two branches - the upper and lower, from which many nerve branches are formed, innervating mainly the mimic muscles of the same half of the face.
In the region of the canal of the facial nerve, the following branches depart: a large stony nerve, a stapedial nerve and a tympanic string. The large stony nerve innervates the lacrimal gland, the stapes nerve innervates the muscle of the same name, and the string tympani provides taste innervation of the anterior 2/3 of the tongue and innervates the sublingual and submandibular salivary glands.
The branches extending from the facial nerve after exiting the stylomastoid foramen innervate: the posterior auricular nerve - the muscles of the auricle, the posterior belly of the digastric muscle and the stylohyoid muscle; temporal branches - the frontal muscle, the circular muscle of the eye, the muscle that frowns the eyebrows; zygomatic branches - the circular muscle of the eye and the zygomatic muscle, buccal branches - the large zygomatic, buccal, laughter muscle, the circular muscle of the mouth and nasal; the marginal branch of the lower jaw - the chin muscle, lips; cervical branch - neck muscles.
Damage symptoms.
a) paralysis of facial muscles
1. central: smoothness of the nasolabial fold and drooping of the corner of the mouth on the side opposite to the lesion (because the upper part of the nucleus of the FN is connected with both hemispheres, and the lower part is only with the opposite, therefore, with supranuclear lesions of the FN, only the lower parts of the mimic muscles suffer)
2. peripheral: paralysis of the entire mimic muscles of the same half of the face: it is impossible to wrinkle the forehead; when the eye is closed, the eyeball turns upward, and its iris goes under the upper eyelid and only the sclera is visible (Bell's symptom); the eye does not close (hare's eye - lagophthalmos); when teeth are bared, the corner of the mouth is drawn to the healthy side, and the smoothness of the nasolabial fold on the side of the lesion becomes even more pronounced; whistling is impossible, speech is difficult; while eating, food falls behind the affected cheek; lacrimation; the superciliary reflex is lost or weakened; in the study of electrical excitability, a degeneration reaction is possible.
The prolonged existence of peripheral paralysis may be accompanied by the development of contracture of the affected muscles, which leads to a narrowing of the palpebral fissure and an increase in the nasolabial fold on the side of the lesion. Sometimes there is a pathological synkinesis of the muscles of the face. In this case, squinting the eye is accompanied by baring of the teeth, and an attempt to bare the teeth causes squinting of the eye on the side of the lesion.
b) when pathological processes accompanied by irritation of the cells of the nucleus or fibers of the facial nerve, there is a tonic spasm of the muscles - facial hemispasm (the mouth and tip of the nose are pulled to the affected side, the eye is closed, the muscles of the chin are contracted, the subcutaneous muscle of the neck is tense).
Diagnosis of the level of damage:
a) at the base of the skull: taste disorders in the anterior 2/3 of the tongue, paralysis of the mimic muscles, dry eyes, decreased salivation and hearing loss or deafness in the ear of the same name. The latter is due to damage to the auditory nerve, which runs next to the facial nerve.
b) in the initial part of the facial canal: paralysis of the mimic muscles, taste disorder in the anterior 2/3 of the tongue, dry eyes, decreased salivation and increased perception of various tastes (hyperacusia), which is associated with impaired innervation of the stapedius muscle.
c) in the area of the canal, down from the large stony nerve, above the tympanic string: paralysis of the mimic muscles on the same half of the face, lacrimation, taste disturbance in the anterior 2/3 of the tongue and a decrease in salivation
d) after leaving the stylomastoid foramen: paralysis of the mimic muscles and lacrimation, the taste is preserved.
If both LNs are affected, the face is amimic, as if clothed in a mask, its usual folds are absent, the closing of the eyelids is difficult, so the eyeballs remain half-open, it is impossible to fold the lips into a tube and close the mouth. In the case of an increase in the mechanical excitability of the facial nerve, a Khvostek symptom appears (tapping with a hammer on the zygomatic arch causes muscle contraction on the same half of the face).
Sometimes, with lesions of the facial nerve, pain is possible, which is explained by the presence of nerve connections him with the trigeminal nerve.
Research methods: the state of innervation of the mimic muscles of the face is mainly determined, and taste sensitivity in the anterior 2/3 of the tongue for sweet and sour is also examined.
The facial nerve (n. facialis) is mixed, has motor, sensory and parasympathetic fibers (Fig. 528).
528. Branches of the facial nerve.
1-rr. temporales; 2-rr. zygomatici; 3-rr. buccales; 4-rr. marginalis mandibulae; 5-r. colli; 6-pl. parotideus; 7-n. facialis.
The motor part of the facial nerve starts from the nucleus, located in the dorsal part of the brain bridge, surrounded by the reticular formation, on the border with the medulla oblongata posteriorly and outward from the superior olive. The intracerebral part of the nerve root rises and goes around the nucleus of the abducens nerve. This bend represents the intracerebral knee of the facial nerve. The facial nerve enters the ventral surface of the brain between the posterior edge of the pons and the olive of the medulla oblongata and enters the internal auditory canal (porus acusticus internus), and then into the canal of the facial nerve of the pyramid of the temporal bone. Initially, the nerve lies horizontally, reaching a large stony foramen (hiatus canalis n. petrosi majoris), near which the nerve makes a turn back and laterally at an angle of 90 °. This first bend of the nerve is called the knee (geniculum n. facialis). Having passed 6-8 mm above the tympanic cavity, the facial nerve forms a second bend and changes horizontal position to vertical. The vertical part of the nerve passes behind the tympanic cavity and through the stylomastoid opening (for. stylomastoideum) enters the posterior jaw space, in which the parotid salivary gland lies. In the thickness of its facial nerve is divided into 5-10 branches, radially diverging towards facial muscles. Branches of the nerve form small and sometimes large loops of the parotid nerve plexus.
A number of branches depart from the motor fibers of the facial nerve.
1. The stapedial nerve (n. stapedius) is very short and thin, departs from the second bend of the facial nerve. Penetrates into the tympanic cavity, ending in the stirrup muscle (m. stapedius).
2. Branch for innervation of the levator muscle soft sky, departs in the facial canal. The motor fibers, together with parasympathetic fibers, exit through the canaliculus chordae tympani into the stony-tympanic fissure at the base of the skull, where they enter the gangl. oticum. The nerve innervates m. levator veli palatini.
3. The connecting branch with the glossopharyngeal nerve (r. communicans cum n. glossopharyngeo) is separated from the nerve near the stylomastoid foramen and along m. stylopharyngeus reaches the pharyngeal wall, connecting with the branches of the glossopharyngeal nerve.
4. The posterior auricular nerve (n. auricularis posterior) departs from the facial nerve on the outer base of the skull near the stylomastoid opening, goes back up, bending around the mastoid process in front. Innervates the occipital belly of the supracranial muscle, the posterior and superior ear muscles.
5. The digastric branch (r. digastricus) is thin, departs below the previous nerve, innervates the posterior abdomen m. digastricus and m. stylohyoideus.
6. Temporal branches (rr. temporales) emerge from the parotid plexus. Among them, the anterior branches are conditionally distinguished (they innervate the upper part of the circular muscle of the eye and the muscle wrinkling the eyebrows), the middle ones - the frontal muscle, the posterior ones - the anterior and partially upper ear muscles.
7. Zygomatic branches (rr. zygomatici), number 2-5, innervate the lower part of the circular muscle of the eye and the zygomatic muscle.
8. Buccal branches (rr. buccales), 2-4 in number, innervate the buccal, circular muscle of the mouth, muscles that raise the angle of the mouth and upper lip.
9. The marginal branch of the lower jaw (r. marginalis mandibulae) is located along the edge of the lower jaw and innervates the muscle of laughter, the chin, the depressors of the corner of the mouth and the lower lip.
10. The cervical branch (r. colli) passes near the angle of the lower jaw to the neck and innervates m. platysma.
The sensitive section of the facial nerve consists of two parts: the first is the fibers of the taste analyzer, arising from the receptors of the taste fields of the tongue, the second is the fibers of general sensitivity.
In the first part, sensitive unipolar cells are located in the knee node (gangl. geniculi), located in the knee of the facial canal. The node has dimensions of 1x0.3 mm. Taste buds are located on 2/3 of the front of the tongue in the taste pores. Taste nerve fibers are included in n. lingualis and leave it at the upper edge of the medial pterygoid muscle, penetrating into the drum string (chorda tympani). Sensitive fibers of the tympanic string enter through the stony-tympanic fissure into the tympanic cavity, pass in its submucosal layer between the long stem of the anvil and the handle of the malleus. From the tympanic cavity through the stony-tympanic fissure they enter the facial canal. Exiting through the porus acusticus internus at the base of the skull, the fibers enter the brain and switch in the sensory nucleus (nucl. tr. solitarii).
The second part of the nerve contains fibers of general sensitivity, which are in contact with receptors located in the skin of the inner surface of the auricle. Their sensitive cells are located in gangl. geniculi.
3. Parasympathetic (secretory) fibers of the facial nerve are sent from the superior salivary nucleus (nucl. salivatorius superior), located in the dorsal part of the brain bridge. The radicular fibers of this nerve exit to the base of the brain next to the motor fibers of the facial nerve and, together with them, enter the facial canal. Preganglionic parasympathetic fibers are divided into two portions and leave the facial canal (Fig. 529).
529. Scheme of vegetative and sensory nodes with nerve fibers located in the head (according to Muller).
Blue line - parasympathetic fibers from the midbrain and boulevard sections, red - sympathetic preganglionic fibers; red intermittent - sympathetic postganglionic fibers. 1 - n. oculomotorius; 2 - n. trigeminus; 3 - n. facialis; 4 - n. glossopharyngeus; 5 - gangl. sublinguale; 6 - gangl. oticum; 7 gangl. sphenopalatinum; 8 - gangl. ciliare.
The first portion is separated in the region of the knee and through the entrance to the canal of the large stony nerve (hiatus canalis n. petrosi majoris) enters the cavity of the middle cranial fossa called the large stony nerve (n. petrosus major) (Fig. 529). This nerve passes through connective tissue torn opening of the skull and enters the pterygoid canal (canalis pterygoideus) of the sphenoid bone. Before entering this canal, the deep stony nerve (n. petrosus profundus), composed of postganglionic sympathetic fibers from the cells of the internal carotid plexus (plexus caroticus internus), joins the large stony nerve. The pterygoid nerve enters the pterygopalatine fossa, where the parasympathetic fibers switch to the II neuron and form the pterygopalatine ganglion (gangl. pterygopalatinum) ().
The following fibers come to the node: parasympathetic - through n. petrosus major, which have contacts with the next neuron in the node; sympathetic - through n. petrosus profundus, which pass through the node and, as part of its branches, reach the vessels and mucous membrane of the nasal cavity and nasopharynx; sensory fibers form branches: rr. orbitales, nasales posteriores superiores, palatini. From the pterygopalatine node, parasympathetic postganglionic fibers also begin, which pass through the nn. pterygopalatini, maxillaris, zygomaticus. In the orbit, they leave the zygomatic nerve, forming an anastomosis with n. lacrimalis. In its composition, they reach the lacrimal gland.
The second portion of the preganglionic parasympathetic fibers continues its path initially through the facial canal, and then passes into the canaliculus chordae tympani, located in the same bundle with sensitive (gustatory) fibers called chorda tympani. The drum string connects to n. lingualis. Its parasympathetic fibers exit the lingual nerve to the submandibular and sublingual salivary glands near the submandibular gland, they form gangl. submandibularis, in the sublingual - gangl. sublingualis. Postganglionic parasympathetic fibers emerge from the nodes for secretory innervation of the submandibular and sublingual salivary glands and mucous glands of the tongue.
Embryogenesis. The motor nucleus is laid on the 4th week of embryonic development near the bottom of the IV ventricle in the column of cells of the tegmentum of the medulla oblongata and comes into contact with derivatives of the II branchial arch. During development, the nucleus of the facial nerve shifts in the ventrolateral direction and its fibers become curved. Axons come into contact with visceral myotomes, where mimic muscles are laid.
Phylogenesis. In fish and amphibians, the facial nerve departs from the medulla oblongata with several roots, having a node into which the lateral and proper facial nerves flow. The lateral nerve innervates the seismosensory organs, which disappear in terrestrial animals, which causes the reduction of this nerve.
The facial nerve itself in aquatic and terrestrial animals has sensory and motor branches. Sensory fibers originate from the taste buds of the mucous membrane oral cavity and side line. In terrestrial animals, the sensitive part of the lateral line disappears, and the head part passes through the tympanic cavity, maintaining contact with the taste buds of the tongue, and is called chorda tympani. Motor fibers innervate the muscles of the suspension and gill cover in fish, the intermaxillary muscle, the muscle that lowers the lower jaw, and the subcutaneous cervical muscles in terrestrial animals. Mammals have a well-developed facial musculature, also innervated by a special branch of the facial nerve, which in humans, due to the development of facial muscles, has received predominant development.
