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n1.doc

Lesson No. 1.
Subject: SPINAL CORD, ITS STRUCTURE AND MEMBRANES; CHILD'S SPINAL CORD.

Purpose of the lesson: learn to find, name and show structural details spinal cord, its shells and intershell spaces, be able to talk about the topographic relationships of the spinal cord and spinal column in an adult and a child.
METHODOLOGICAL INSTRUCTIONS.
It is necessary to independently study general data about the nervous system: dividing it according to a topographic principle into central and peripheral sections, as well as, in accordance with the division of the body into soma and viscera, dividing it into somatic / animal / and autonomic / sympathetic and parasympathetic / systems. Have a clear understanding of the structural and functional unit nervous system– neuron and types of neurons from both structural and functional points of view.

When studying the spinal cord, find and be able to show the cervical and lumbosacral thickenings, the conus medullaris with the filum terminale, grooves, the anterior median fissure and the posterior median sulcus dividing the brain into two symmetrical halves, the anterior and posterior lateral sulci dividing each half of the brain into the anterior , lateral and posterior cords, spinal (intervertebral) node; anterior (ventral) and posterior (dorsal) roots, as well as the trunk of the spinal nerve, called by neurologists the cord ( funiculus ).

You need to know that the activity of the nervous system is based on a reflex. This is a response to any (external or internal) irritation, independent of our consciousness. The material basis of the reflex is the reflex arc. There are simple and complex reflex arcs. A simple reflex arc, characteristic of the spinal cord, is represented by two or three neurons. Remember that the first neurons (sensitive, receptor cells) always lie outside the brain - in the spinal ganglia or in the ganglia of the cranial nerves.

In a three-member spinal reflex arc (see diagram), the first perceiving (receptor) neurons are pseudounipolar cells (1) lying in the spinal (intervertebral) nodes. The peripheral processes of these cells - dendrites (1a) - follow to organs (skin, bones, joints, muscles), ending in them with perceptive devices - receptors, transforming perceived irritation into nerve impulses. The central processes - axons (1b), uniting into a bundle called the posterior (dorsal) root, enter through the posterior lateral groove into the spinal cord and end on the cells of the dorsal horn, which are the second neurons (2). Their axons approach motor cells anterior horn - 3rd neurons of the arc. The axons of these cells (3a) exit the spinal cord through the anterior lateral sulcus in the form of an anterior root and are directed to the effector organs. Reflex mechanism: the irritation received by the receptor is converted into a nerve impulse, which along the dendrites (1a) reaches the bodies of pseudounipolar cells (1) of the intervertebral node and along their axons (1b) is transmitted to the bodies of interneurons (2), through which it enters 3 neurons (3 ), which send orders to the working organs - muscles, causing them to contract. An example of such a reflex reaction is the withdrawal of a hand, independent of our consciousness, when unexpectedly touching a hot or sharp object.

In a two-term reflex arc, where there is no interneuron and the first neuron comes into contact directly with the motor (effector) neuron, the response (reflex) is much faster.

Recent studies (P.K. Anokhin, N.A. Bershtein, etc.) have significantly supplemented our views on the mechanism of reflex activity. It turned out that between the working organ (muscle, gland, etc.) and the nerve centers, in addition to the elements of the reflex arc, there is feedback (“reverse afferentation”), thanks to which self-testing and correction of the work of the organ in each this moment. This can be represented as follows: when a muscle that has received signals from effector neurons (3) begins to contract, the receptors (proprioceptors) embedded in it are irritated - muscle spindles, which continuously send signals to the center about the progress of work at each given moment, which allows the center to carry out appropriate corrections, regulating the level of metabolic processes in the muscle and its tone. This is how the mechanism works feedback, having the character of a closed circle (ring). Thus, the reflex act as a whole can be represented in the following sequence (see Fig. 2):

1) receptor neuron of the intervertebral node, receiving impulses from skin receptors;

intercalary/associative/ dorsal horn neuron;

3) effector /motor/ neuron of the anterior horn, causing muscle contraction;

4) a receptor neuron that receives impulses from the proprioceptor (muscle spindle);

gamma motor neuron of the lateral horn, which regulates metabolism in the muscle and proprioceptor /muscle spindle/;
peripheral autonomic /sympathetic/ neuron lying in the peripheral sympathetic node, through which the center /gamma motor neuron/ corrects muscle function.

The presence of such closed circular/ring/nerve feedback chains allows for constant, moment-to-moment corrections of any reactions of the body to any changes in the conditions of the internal or external environment. Without feedback mechanisms, it is impossible for living organisms to adapt to their environment.

Having studied the structure of the reflex arc and the feedback mechanism, the student should be able to draw diagrams and find the elements of the arc on preparations of the spinal cord.

By the end of the lesson, the student should have a good knowledge of the following:

The posterior /dorsal/ root is formed by axons /1b/ of sensory cells /1/ of the intervertebral ganglion, entering the spinal cord through the posterior lateral sulcus;
The anterior /ventral/ root is formed by axons /3a/ motor /effector/ cells /3/ of the anterior horn, and exits the spinal cord through the anterior lateral sulcus;
The trunk /4/ of the spinal nerve / cord/ is formed as a result of the connection of the anterior root with the dendrites of pseudounipolar cells /1/ of the intervertebral node;
The spinal cord consists of 31 - 33 segments: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1-3 coccygeal.
A segment is an area of white and gray matter corresponding to a pair of spinal nerves and their roots;
The growth of spinal cord segments is uneven: the thoracic segments grow most rapidly, especially Th 5 -Th 7, the cervical and especially the lumbar and sacral segments grow more slowly. Until three months of embryonic development, the spinal cord occupies the entire spinal canal, and then the spine begins to grow faster and by the time of birth the lower end of the brain reaches the level of the lower edge of the third lumbar vertebra, so puncture can only be done between the spinous processes of the 4th and 5th lumbar vertebrae. By 5-6 years, the lower end of the spinal cord reaches the level of 1-2 lumbar vertebrae, which corresponds to the level of an adult.
Of great practical importance is knowledge of the topographic relationships of segments and vertebrae (skeletotopy of segments): the cervical and upper thoracic segments are located 1 vertebra above, the middle thoracic segments are located at 2 vertebrae, the lower thoracic segments are located at 3 vertebrae, the lumbar and sacral segments are located in the area of the conus medullaris at the level of XII thoracic and first lumbar vertebrae. As a result, the place where the roots exit the brain does not correspond to the level of the vertebral foramina, and in the lumbar part of the spinal cord the roots descend to the corresponding intervertebral foramina parallel to the filum terminale, enveloping it and the medullary cone with a bundle called the cauda equina ( cauda equina ). It is formed by the roots of the 4 lower lumbar, 5 sacral and coccygeal nerves.

Drug: Skeleton - I. Spinal cord in the spinal canal - I. Isolated spinal cord - 2. Brain I.

Literature: M.G.Prives, N.K.Lysenkov, V.I.Bushkovich Human anatomy. M., “Medicine”, 1985, pp. 473-485, 489-491. V.N. Tonkov. Textbook of normal human anatomy. M., 1962, pp. 559-575. R.D. Sinelnikov. Atlas of human anatomy. M., 1979.

Tomsk State University Psychology faculty

Lectures on anatomy and physiology of the central nervous system

Lectures on anatomy and physiology of the central nervous system / Author S.A. Bogomaz. - Tomsk: TSU, 2001. - 61 p.

This manual was created with the aim of systematically presenting information about the structure and functional specialization of the parts of the central nervous system contained in various educational and scientific publications.

When compiling methodological manual the material was selected in such a way as to provide a unified approach to the study of the parts of the brain and spinal cord and to facilitate the perception of the educational material.

The methodological manual is presented according to the curriculum for the study of the central nervous system, used at the Department of Genetic and Clinical Psychology of TSU.

Neurobiology is the general name for the branch of science that studies the nervous system (NS) and its main organ, the brain. It includes analysis of the functioning of the neural network at many levels, from consideration of the chemical structure of individual molecules to the study of complex behavioral phenomena.

In the 70s, within the framework of neurobiology, scientists formulated the so-called “Central Dogma”. It goes like this: all the normal functions of a healthy brain and all their pathological disorders, no matter how complex they may be, can ultimately be explained based on the properties of the basic structural components brain

Basic concepts of NS

1. The NS acts throughout the entire body. It is a bodily organ that is responsible for:

 ability to reproduce the world and react to it;

 for coordinating the functions of other organs on which the existence of the organism depends, for example, functions such as nutrition, respiration, movement and reproduction;

 for storing, organizing and retrieving information about past experiences.

2. Individual functions of the NS are carried out by its subsystems, organized in accordance with their purpose. In other words, the implementation of each of the brain functions is assigned to separate systems. The relationship of parts within each system is most easily explained using the concepts of rank or hierarchy. In addition, there are specific and very important connections between certain parts of the NS.

Jo Godefroy writes that if a building is the NS, and a floor is one or another part of the brain, then the higher the floor, the more complex, although not necessarily more “elevated,” functions it performs.

Further, this scientist-psychologist continues: “perhaps what happens inside the building of the National Assembly is most reminiscent of the operation of parts of a television receiver or computer when a flow of electronic information passes through them. At the same time, various electronic components of these devices recognize the nature of the signals and respond only to those for which they are programmed; at the same time, other components filter out unnecessary or unwanted waveforms. NS components also exhibit electrical activity. And although we do not have sufficient grounds to consider them living transistors, today this analogy can be considered the most successful.”

In order for the brain to function effectively, the flow of signals passing in various directions in the nervous system must be controlled by unusually sensitive mechanisms that control these flows and prevent chaos. The NS is conventionally divided into 2 parts: somatic and vegetative (autonomous). The somatic nervous system innervates mainly striated skeletal muscles and skin, and provides communication between the body and the external environment. The autonomic nervous system innervates all internal organs, glands, smooth muscles of organs and skin, blood vessels and the heart, and also ensures metabolic processes in all organs and tissues.

The nervous system is also divided into central (CNS) and peripheral. In turn, the central nervous system includes the brain and spinal cord, and the peripheral nervous system includes nerves, ganglia and nerve plexuses.

Spinal cord

(SM) lies in the spinal canal and is a cylindrical cord, flattened from front to back. Its length in an adult is on average 42-45 cm and its cross-sectional area is 1 cm2. Weight - 34-38 g.

At the top, the SC passes into the medulla oblongata, and at the bottom it ends with a conical point. The terminal filament extends downwards from the cone and is attached to the second lumbar vertebra. The spinal cord along its length contains two thickenings - cervical and lumbar. They correspond to the exit from the SC of the nerve roots of the upper and lower extremities.

Spinal cord:

1–posterior cord; II—lateral cord; III – anterior cord; 1–medial ascending tract (Golle); 2–lateral ascending pathway proportional to sensitivity (Burdach): 3–spinal ganglion; 4-receptor; 5–7,9–nuclei of gray matter; 8–performing organ; 10- ; 11 – central channel; a – posterior spinocerebellar tract; b–lateral corticospinal tract; d – lateral spinothalamic tract; e – ventral spinothalamic tract; e-reticulospinal tract; g – anterior spinocerebellar tract; h–

vestibulospinal tract; i–anterior corticospinal tract

External structure. The deep anterior median fissure runs along the anterior surface of the spinal cord, and the superficial posterior median sulcus runs along the posterior surface. They divide the SM into two symmetrical halves.

On the right and left sides, the spinal nerve roots emerge from the spinal cord. The anterior roots consist of axons of motor and autonomic neurons, the bodies of which are located in the SC. The dorsal roots consist of the axons of sensory neurons, the bodies of which are located in the spinal ganglion. In total, 31 pairs of roots emerge from each side along the SM. The anterior and posterior roots at the inner edge of the intervertebral foramen merge with each other, forming the trunk of the spinal nerve. The trunk is usually short, since after leaving the intervertebral foramen the nerve splits into its main branches.

The area of gray matter of the SC with adjacent white matter, corresponding to two pairs of roots, is called a segment. According to the number of roots, 31 segments are distinguished: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal. Sometimes there are 3 coccygeal segments.

In the intervertebral foramen, near the junction of both roots, the dorsal root has a thickening - the spinal ganglion, containing neurons, the axons of which go to the SC as part of the dorsal roots, and the dendrites pass as part of the spinal nerve.

The structure of the somatic reflex arc . The activity of the nervous system (NS) is based on a reflex. A reflex is the body's response to irritation, carried out and controlled by the central nervous system.

The anatomical path of the reflex is called a reflex arc. It consists of a chain of neurons connected by synapses.

Synapses provide unidirectional conduction of a nerve impulse along a reflex arc.

In a simple three-part reflex arc:

the first neuron (sensitive, afferent, receptor) lies in the spinal ganglion or sensory ganglia of the head;

the second neuron (intercalary, intermediate, associative) lies in the dorsal horns of the SC (see below) or the nuclei of the brain stem;

the third neuron (motor, efferent) lies in the anterior horns of the SC or nuclei of the brain stem.

The nerve impulse passes from the receptor along the dendrite, body and axon of the first neuron to the dendrite or body of the second neuron and along the axon of the second

the neuron moves to the third. Along its axon, which is part of the spinal nerve, the nerve impulse reaches the working organ (effector).

Internal structure. The SM consists of gray matter, formed by the accumulation of neuronal cell bodies and their dendrites, and overlying white matter, consisting of axons covered with a myelin sheath.

Gray matter occupies the central part of the SC and forms 2 vertical columns in it. One of them is located in the right half of the SM, the other in the left. The columns are connected to each other by gray spikes. In the middle of the gray matter there is a narrow central canal, ending in the terminal ventricle, and at the top communicating with the cavity of the fourth ventricle of the brain. The canal contains cerebrospinal fluid.

In each column, 2 columns can be distinguished, and in the thoracic and sacral sections there is also a lateral one. On a cross section of the brain, these pillars look like horns, and the entire gray matter looks like the letter H or a butterfly with outstretched wings. The posterior horns contain sensory neurons, the anterior horns contain motor neurons, and the lateral horns contain autonomic neurons. Moreover, in the thoracic region of the SC, neurons of the sympathetic nervous system are located in the lateral horns, and in the sacral region, neurons of the parasympathetic nervous system are located.

The white matter of the SC forms anterior, posterior and lateral funiculi around the gray matter. They consist of processes of neurons that form 2 groups of pathways: propriospinal and supraspinal.

The propriospinal tracts are divided into short ones, connecting the nearest segments of the SC, and long ones, connecting distant segments of the SC. These pathways are formed predominantly by processes of intercalary and afferent neurons. The function of the propriospinal tract is to carry out unconditioned reflexes.

Supraspinal tracts provide communication between the SC and the brain. These pathways are divided into ascending (afferent) and descending (efferent). Along these pathways from receptors in the skin, muscles, tendons and joints, as well as from internal organs information enters the higher parts of the brain. From them, impulses depart in a descending direction to the neurons of the SC, changing the activity of skeletal muscles and internal organs. The activity of the SC in humans is largely subordinate to the coordinating influences of the overlying parts of the central nervous system.

The ascending tracts pass through the posterior cords of the white matter of the SC and connect it with the medulla oblongata. Function of the pathways: providing conscious proprioceptive (musculo-articular) sensitivity.

The lateral funiculi contain both ascending and descending pathways connecting the SC with the cerebellum, thalamus, midbrain and cerebral cortex. Their function: providing unconscious proprioceptive sensitivity (cerebellum), temperature-pain and tactile sensitivity (thalamus), providing unconscious motor ac-

activity (red nucleus of the midbrain) and consciousness motor activity(bark).

The anterior funiculi contain descending tracts. Their function: providing unconscious motor activity to visual and auditory stimuli (orienting reflex regulated from the quadrigeminal tuberosities), conscious motor activity (cortex), unconscious motor activity (medulla oblongata and nuclei of the reticular formation).

SM provides a quick protective reaction of the body, for example, in the event of a burn or injection. It contains reflex centers muscles of the trunk, limbs and neck. With their participation, tendon reflexes, stretch reflexes, flexion and extension reflexes, and various reflexes that support posture are carried out. SM is involved in the regulation of various autonomic functions of the body, changing the activity of internal organs.

Ensuring the implementation of vital functions, the spinal cord develops earlier than other parts of the central nervous system. On early stages fetal SM fills the entire cavity of the spinal canal. Then the spinal column overtakes the SM in growth. By the time of birth, the SM ends at the level of the 3rd lumbar vertebra. In a newborn, the length of the SM reaches 14-16 cm, and by the age of 10 it doubles. The thickness of the SM grows slowly. On a cross section of the spinal cord of young children, the most noticeable predominance of the anterior horns over the posterior ones is noted.

Sheaths of the spinal cord. It is surrounded by connective tissue membranes: the outer one is called hard, the middle one is called arachnoid, and the inner one is called soft.

The outer and middle membranes are separated from each other by the subdural space, and the middle and inner membranes are separated from each other by the subarachnoid (subarachnoid) space.

The dura mater has the strongest walls compared to other membranes of the spinal cord. It does not adhere closely to the periosteum, which covers the spinal canal from the inside. Between them there is adipose tissue and the internal vertebral venous plexus. At the top, the dura mater fuses with the edges of the foramen magnum of the skull and continues into the dura mater of the brain. Below, the hard shell of the SC ends in the form of a thread that is attached to the coccyx.

The arachnoid membrane has the appearance of a transparent sheet, without blood vessels, adjacent to the hard shell from the inside, fused with it near the intervertebral foramina with the help of crossbars. The arachnoid membrane is connected to the soft shell through numerous bundles.

The subarachnoid space is filled with cerebrospinal fluid and communicates with the subarachnoid space of the brain.

The pia mater directly surrounds the spinal cord and fuses with it. It contains vessels that supply blood to the SC and its membranes.

Brain

The brain is traditionally divided into three parts: the cerebrum, the cerebellum, and the brainstem. Most of the brain is occupied by the cerebrum (hemispheres).

There is a distinction between the base of the brain, or basal surface, and the dorsal surface.

Dorsal surface. Both hemispheres are separated from each other by a longitudinal fissure. In its depths, the hemispheres are connected by the corpus callosum and the anterior commissure of the brain, which consist of nerve fibers running transversely from one hemisphere to the other. The entire surface of the cerebral cortex is formed by convolutions, which are separated from each other by grooves. Due to this, there is a significant increase in the surface of the cerebral cortex (up to 2500 cm2 in an adult). All these structures will be examined in more detail when studying the telencephalon.

Basal surface. In the anterior part of the base of the brain, a longitudinal groove of the brain penetrates here. Laterally, almost parallel to this groove, the tract of the olfactory nerve stretches. In front, it begins with the olfactory bulb, into which the fibers of the 1st pair of cranial nerves - the olfactory nerves - enter, and ends with the olfactory triangle. Behind it lies the anterior perforated substance, through which blood vessels penetrate into the medulla.

The optic chiasm is visible on the basal surface. In front, the 2nd pair of cranial nerves enters it - the optic nerves, which, after the chiasm, continue into the optic tracts. Posterior to the chiasm is a gray tubercle that continues into a narrow funnel to which the pituitary gland is suspended. The mastoid (mamillary) bodies are adjacent to the gray tubercle behind.

The cerebral peduncles are derivatives of the midbrain and are two white cords diverging anteriorly and upward.

Cranial nerves

Places of exit of cranial nerves onto the basal surface: The first two pairs of cranial nerves have already been described above.

3. Oculomotor nerves (III) exit medially from the cerebral peduncles.

4. The trochlear nerves (IV) exit lateral to the cerebral peduncles.

Both nerves regulate eye movements and innervate the ciliary muscle and the muscle that constricts the pupil.

5. Trigeminal nerves (V), emerge at the border between the pons and the middle cerebellar peduncle.

Innervates the chewing muscles; controls pain and temperature sensitivity of the scalp, nasal mucosa, mouth, etc.; conducts proprioceptive sensitivity of the masticatory muscles and muscles of the floor of the mouth;

6. Abducens nerves (VI) - exit at the border between the pons and the pyramids of the medulla oblongata.

7. Facial nerves (VII) - exit lateral to the abducens nerves.

8. vestibulocochlear nerves (VIII) - exit slightly lateral to the facial nerves.

9. Glossopharyngeal nerves (IX) exit behind the olives.

10. Vagus nerves (X) - exit below the glossopharyngeal nerves.

11. Accessory nerves (XI) - exit below the vagus nerves.

12. Hypoglossal nerves (XII) - exit between the pyramids and olives of the medulla oblongata.

Medulla

The medulla oblongata is a direct continuation of the spinal cord and therefore retains all its morphological structures.

External building. There is a groove in front of the medulla oblongata (PM), and a fissure in the back. On the sides of the gap there are roller-like projections - pyramids, formed by fibers of the pyramidal (corticospinal) tract. These pathways form a partial decussation in the lower part of the PM. In this case, the uncrossed part of the fibers goes on its side in the anterior ones (corticospinal anterior tract), and the crossed part goes in the lateral cords of the spinal cord on the opposite side (in the form of a corticospinal lateral tract).

Lateral to the pyramids there are convex oval formations - the inferior olives, corresponding to the lateral cords of the SC.

The posterior cords of the PM pass below into the cords of the same name of the SM, and above into the inferior cerebellar peduncles. The posterior cords on each side are divided into two bundles: the medial - gentle (Gaull's path) and the lateral - wedge-shaped (Burdach's path). These bundles end with the corresponding tubercles, in which the second neurons of the Gaulle and Burdach pathways are located. The axons of these neurons go in a ventral direction, cross over and move to the opposite side, forming a medial loop.

Medulla:

1–pyramids; 1a – cross; 2–lower olives; 3–anterior spinocerebellar tract; 4– posterior spinocerebellar tract; 5-sphenoid nucleus; 6–tender core;7–; 8-

reticular formation; 9 – vestibulospinal tract; 10 – path from the quadrigeminal tuberosities; 11–rednuclear spinal tract; 12–fibers of the inter-olive layer; 13 – intersection of the paths of Gaulle and Burdakh; IX–XII–nuclei of cranial nerves

The medulla oblongata does not have a strict division into gray and white matter. Gray matter is located in white matter in separate groups - nuclei. These nuclei take part in the implementation of reflexes that maintain a person’s posture and reflexes that ensure the movement of the body in space. In addition, the medulla oblongata regulates the activity of the lacrimal and sweat glands, salivation, the secretory function of the gastric glands, and affects the excretion of bile.

The PM contains:

 vital centers of respiration, circulation and digestion associated with the vagus nerve;

 centers of gag and swallowing reflexes;

 nuclei IX-XII of the cranial nerve;

 ascending and descending paths.

Pons

The pons is located on the basal surface of the brain, with its dorsal part facing the cavity of the fourth ventricle.

The bridge consists of a dorsal part - the tire and a ventral part - the base. Between them there is a massive bundle of transversely running fibers of the auditory pathway - the trapezoid body. The first neurons of this pathway are located in the spiral ganglion, which lies in the cochlea of the inner ear. The axons of these neurons go to the ventral and dorsal cochlear nuclei of the vestibular nerve (VIII). The second neurons of the auditory pathway are concentrated in these nuclei.

I – bridge tire; II—trapezoid body; III – bridge base; 1-; 2–medial loop; 3-nuclei of the trapezoid body; 4–corticospinal tract; 5-bridge cores; 6– upper olive; 7–descending extrapyramidal tracts; 8-reticular formation

From the ventral nuclei, axons go to the opposite side, switching along the way to the cells of the olivary nuclei and the own nuclei of the trapezoid body (third neurons), lying on their own or the opposite side, making a crossover. The axons of 3 neurons on the opposite side form a lateral loop going to the subcortical centers of vision (see section “Diencephalon”). The axons of the cells of the dorsal nuclei run along the bottom of the rhomboid fossa, reach the median groove of the fossa and plunge into the pons, where they join the fibers of the trapezoidal body, pass to the opposite side (for the most part) and also participate in the formation of the lateral loop.

Both transverse and longitudinal fibers pass through the base of the bridge. The longitudinal fibers include the corticospinal tract, which passes here in transit; corticonuclear tract, partially ending on the pontine motor nuclei V, VI VII of the cranial nerve; corticomontine pathway.

The system of cross connections is represented by the cerebellopontine tract, coming from the pons' own nuclei, to which the nerve fibers of the corticomontine tract switch. The cerebellopontine tracts go to the opposite side, making a decussation, and through the middle cerebellar peduncles they enter the cerebellar cortex.

The pons contains numerous centers responsible for eye reflexes, reflex blinking, intestinal motility, urination, etc.

The pons contains:

nuclei of the V-VIII cranial nerves;

lateral lemniscus, consisting of fibers of the auditory tract; ascending tracts: lateral lemniscus, medial lemniscus;

descending pathways: corticospinal and corticonuclear tracts (pyramidal), corticopontine tract;

transverse tracts: cerebellopontine tract.

Cerebellum

The cerebellum is located in the postcranial fossa, the floor of the occipital lobes of the cerebral hemispheres, covering the pons and medulla oblongata.

There are two hemispheres and a narrow part located between them - the worm. The superficial cerebellum is covered with a layer of gray matter or cortex, which forms convolutions - sheets separated from each other by grooves.

Cerebellar neurons have numerous connections with each other and with neurons in other parts of the central nervous system. This ensures ongoing participation

Name: Anatomy of the central nervous system. Short course

The year of publishing: 2014
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"Siberian State medical University»

Ministry of Health of the Russian Federation
FUNCTIONAL MORPHOLOGY

PERIPHERAL NERVOUS SYSTEM

AND ANALYZERS

Study guide for students

BBK E76ya73+E991.5ya73

F947
F947 Functional morphology of the peripheral nervous system and analyzers: a textbook for students / I.V. Sukhodolo, E.A. Gereng, A.N. Dzyuman, V.A. Kazakov, I.V. Milto. – Tomsk, 2013. – 128 p.

The tutorial consists of 3 sections. They provide information about the structure of the peripheral nervous system, sensory organs and pathways of the brain and spinal cord. An information block and illustrative material complements each part of the textbook. For the purpose of self-control, a list is provided test tasks, situational problems and answers to them.

The textbook is written on the discipline “Morphology: human anatomy, histology, cytology” in accordance with the Federal State Educational Standard of Higher Education vocational education in specialties: medical biochemistry; medical biophysics; medical cybernetics.

UDC 611.83.068:612.815](075.8)

BBK E76ya73+E991.5ya73

REVIEWERS:

Medvedeva N.N.– Doctor of Medical Sciences, Professor, Head of the Department of Human Anatomy, Krasnoyarsk State Medical University named after. prof. V.F. Voino-Yasenetsky Ministry of Health of Russia

Yanin V.L.– Doctor of Medical Sciences, Professor, Head of the Department of Histology, State Budgetary Educational Institution of Higher Professional Education, Khanty-Mansi Autonomous Okrug, Yugra, Ministry of Health of Russia
Approved and recommended for publication by the Central Methodological Council of the Siberian State Medical University of the Ministry of Health of Russia (Minutes No. 1 of February 13, 2013).
© I.V. Sukhodolo, E.A. Gereng, A.N. Dzyuman, V.A. Kazakov, I.V. Milto, 2013

1. MORPHOLOGY OF INTEGRATIVE SYSTEMS 5

1.1. FUNCTIONAL MORPHOLOGY OF SPINAL NERVES 5

1.3. FUNCTIONAL MORPHOLOGY OF THE AUTONOMIC NERVOUS SYSTEM 45

2.1. FUNCTIONAL MORPHOLOGY OF VISUAL, OLfactory AND GASTE ANALYZERS 60

1. MORPHOLOGY OF INTEGRATIVE SYSTEMS

1.1. FUNCTIONAL MORPHOLOGY OF SPINAL NERVES

The peripheral nervous system is classified according to morphological and functional characteristics.

The peripheral nervous system has two divisions: spinal (31 pairs of spinal nerves) and cranial (12 pairs of cranial nerves).

In addition, the peripheral nervous system is divided into somatic

(innervating the soma and establishing the relationship of the body with the external environment) and vegetative (innervating the organs and regulating internal processes in the body).

The somatic spinal section includes: spinal nerve roots, spinal nerve trunk, spinal ganglion, branches of spinal nerves, nerve plexuses, peripheral nerves, nerve endings.

There are 31 pairs of spinal nerves (nn. spinales), which correspond to segments of the spinal cord. There are 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and 1 coccygeal segments.

The spinal nerve is formed by the fusion of two roots of the spinal cord: posterior, sensitive, which is a collection of dendrites of pseudounipolar nerve cells of the spinal ganglion and anterior, motor, which is a collection of axons of motor neurons of the anterior horns of the gray matter of the spinal cord.

The anterior and posterior roots merge and form a short (up to 1.0 cm) trunk of the spinal nerve. After leaving the intervertebral foramen, each spinal nerve divides into 4 branches:

1 - posterior branch - for innervation of the back muscles and the skin above them;
2 - anterior branch - for innervation of the limbs;
3 – meningeal branch - for innervation of the spinal cord membranes;
4 - connecting branch - for connection with the sympathetic trunk (C 8 - L 3).

In terms of fiber composition, spinal nerves are mixed (contain sensory and motor fibers).

The anterior branches of the spinal nerves retain a metameric structure and correspond to segments of the spinal cord only in the thoracic region - 12 pairs of intercostal nerves.

In the remaining sections, the segmentation of the spinal nerves is lost and the anterior branches from adjacent segments intertwine to form plexuses.

The following plexuses are distinguished : cervical (plexuscervicalis), shoulder (plexusbrachialis), lumbar (plexuslumbalis) and sacral (plexussacralis).

Cervical plexus

Cervical plexus (plexuscervicalis) formed by the anterior branches of the four superior cervical nerves (WITH 1 -WITH 4 ). This plexus is located on the deep muscles of the neck and is covered from above by the sternocleidomastoid muscle. Cutaneous (sensory), muscular (motor) and mixed (phrenic nerve) branches are formed from the cervical plexus.

The cutaneous branches include: lesser occipital nerve (n. occipitalisminor) (WITH 2 -WITH 3 ) innervates the skin of the posterolateral surface of the neck and head. Greater auricular nerve (n. auricularismagnus) (WITH 3 ) goes to the skin of the auricle and external auditory canal. Transverse nerve of the neck (n.transversuscolli) (WITH 2 - WITH 3 ) innervates the skin of the anterior surface of the neck. Supraclavicular nerves (nn. supraclaviculares) (WITH 3 - WITH 4 ) numerous, innervate the skin within the supraclavicular and subclavian fossae, deltoid and superolateral part of the scapular region.

Muscular branches(WITH 3 - WITH 4 ) innervate the deep muscles of the neck, the muscles located below the hyoid bone, as well as the sternocleidomastoid and trapezius muscles (together with the accessory nerve (XI pair of cranial nerves).

The only mixed peripheral nerve of the cervical plexus is phrenic nerve (n. phrenicus) (WITH 3 - C 5 ) , which contains motor and sensory fibers. The motor fibers of the phrenic nerve innervate the diaphragm, sensory fibers - the pleura, pericardium, parietal peritoneum covering the diaphragm, and liver capsule (Fig. 1).

Rice. 1. Formation, composition and areas of innervation of the branches of the cervical plexus (I.V. Gaivoronsky, 2009)

Brachial plexus

Brachial plexus (plexusbrachialis) formed by the anterior branches of the four inferior cervical nerves and most of the anterior branch of the first thoracic nerve (C 5 – C 8 – (Th 1 ).

According to V.N. Shevkunenko, there are two main types of brachial plexus: main, with a small number of nerve connections between the main nerve trunks (more often found in hypersthenics), and scattered, characterized by a tendency to multiple splitting of the main nerve trunks (more often observed in asthenics). In childhood, the brachial plexus occupies a relatively large area, and its main trunks are located more obliquely.

The brachial plexus exits through the space between the anterior and middle scalene muscles into the supraclavicular fossa, located above and posterior to the subclavian artery. The brachial plexus forms 3 large bundles - lateral, medial and posterior, which are located in the axillary fossa and surround the axillary artery (Fig. 2).

The brachial plexus forms short and long branches, which are localized, respectively, in the supraclavicular and subclavian regions.

The short branches of the brachial plexus are located in the supraclavicular region and innervate the muscles of the shoulder girdle. The largest nerve of the short branches is the axillary nerve (n. axillaris) . It innervates the shoulder joint, deltoid and teres major muscles.

The long branches of the brachial plexus are divided into two groups:

The anterior group, the branches of which innervate mainly the flexors and pronators;

The posterior group, the branches of which innervate mainly the extensors and supinators.

Rice. 2. Formation, composition and areas of innervation of the branches of the brachial plexus (Yu.A. Orlovsky, 2008)

The anterior group includes the following nerves:

median ( n. medianus) (WITH 5 – Th 1 ), innervates the anterior muscle groups of the forearm with the exception of the flexor carpi ulnaris and the deep flexor of the digitorum. In addition, the median nerve sends branches to the capsules of the ulnar, radiocarpal and interphalangeal joints of the 1st, 2nd, and 3rd fingers (Fig. 3);

Rice. 3. Areas of innervation of the median and ulnar nerve

(Yu.A. Orlovsky, 2008)

ulnar (n. ulnaris) (WITH 7 - Th 1 ), on the forearm it innervates the flexor carpi ulnaris and the deep flexor digitorum. On the palmar side, the ulnar nerve innervates the skin of the fourth and fifth fingers, the muscle that opposes the thumb, the flexor pollicis, and the flexor brevis and longus of the little finger (Fig. 3);
medial cutaneous nerve of the shoulder (n. cutaneusbrachiimedialis) (C 8 - Th 1 ) innervates the skin of the medial region of the shoulder;
medial cutaneous nerve of the forearm (n. cutaneusantebrachiimedialis)(C 8 - Th 1 ), innervates the skin of the medial forearm;
musculocutaneous (n. musculocutaneus) (C 5 -WITH 7 ) , innervates the anterior group of muscles of the shoulder, and also gives a cutaneous branch to the outer surface of the forearm.

The posterior group is represented by the radial nerve ( n. radialis) (WITH 5 - Th 1 ). The radial nerve runs along the back of the shoulder and innervates all the extensors of the shoulder, forearm, and the skin over them.

The superficial branch follows downwards in the radial groove and under the tendon of the brachioradialis muscle passes to the back of the hand and innervates the distal, proximal phalanges of the II and radial half of the III fingers.

A deep branch perforates m. supinator, giving it branches, and passes to the posterior surface of the forearm, where it innervates all muscles (extensors) and sends fibers to the radiocarpal, intercarpal and carpometacarpal joints (Fig. 4).

Short (muscular) branches go to the psoas muscles. The long branches of the lumbar plexus include:

iliohypogastric nerve ( n. Iliohypogastricus) (Th 12 - L 1 ) innervates the abdominal muscles, skin of the buttocks, inguinal canal;
ilioinguinal nerve (n. ilioinguinalis) (L 1 ) innervates the skin of the genital organs;

Rice. 4. Areas of innervation of the radial nerve

(Yu.A. Orlovsky, 2008)

Intercostal nerves

Intercostal nerves (nervusintercostalis) formed by the anterior branches of the spinal nerves originating from the 12 thoracic segments (Th 1 - Th 12 ). They do not form plexuses and go in the intercostal spaces. The upper 6 pairs of intercostal nerves reach the edge of the sternum, the lower 6 branch in the thickness of the abdominal wall. Muscular and cutaneous branches depart from the intercostal nerves. Muscle nerves give branches to the external and internal intercostal muscles, as well as the rectus, external and internal oblique and transverse abdominal muscles. Cutaneous branches innervate the anterolateral surface of the chest and abdomen. In addition, the intercostal nerves send branches to the costal pleura and the parietal peritoneum of the anterior and lateral walls abdominal cavity(Fig. 5)

Rice. 5. Areas of innervation of the intercostal nerve

(A.V. Triumphov, 2008)

Lumbar plexus

Lumbar plexus (plexuslumbalis) formed by the anterior branches of the twelfth thoracic and third-fourth lumbar segments (Th 12 ― L 3,4 ). It is located in the thickness of the psoas major muscle, anterior to the transverse processes of the lumbar vertebrae. The lumbar plexus gives off short and long branches (Fig. 6).

Rice. 6. Areas of innervation of the lumbar plexus

(I.V. Gaivoronsky, 2009)

genitofemoral nerve (n. genitofemoralis) (L 1 ) innervates the skin of the thigh and the membrane of the testicle;
lateral cutaneous nerve of the thigh (n. cutaneusfemorislateralis) (L 2 - L 3 ) innervates the skin of the thigh to the knee;
femoral nerve (n. femoralis) (L 2 - L 4 ) innervates the muscles of the anterior thigh and the skin above them;
obturator nerve (n. obturatorius) (L 2 - L 5 ) innervates the obturator externus muscle, the muscles of the medial group of the thigh, gives branches to the hip joint and to the skin of the medial surface of the lower half of the thigh.

Sacral plexus

Sacral plexus (plexussacralis) formed by part of the anterior branches of the IV-V lumbar nerves and branches of the four upper sacral nerves (L 4,5 - S 1-4 ). The sacral plexus is divided into short and long branches.

The short branches of the sacral plexus include the following nerves:

muscle branches (n. musculares) ( L 1 - S 2 ), innervate the pelvic muscles;

superior and inferior gluteal nerves (n. gluteussuperioretinferior)

(L 4 - S 1 ), carry out innervation of the gluteal muscles and the skin over them;

pudendal nerve (n. pudendus) (S 1 - S 4 ) innervates the genital organs and contains many autonomic fibers.

The long branches of the sacral plexus include:

posterior cutaneous nerve of the thigh ( n. cutaneusfemorisposterior) (S 1 - S 3 ) innervates the skin of the thigh, calf area, perineum;
sciatic nerve (n. ischiadicus) (L 4 -S 3 ) - the largest nerve in the human body, exits the thigh under the flexors of the leg, in the popliteal fossa it divides into the thicker, medially located tibial nerve (n. tibialis) and laterally – peroneal nerve (n. fibulares);
tibial nerve (n. tibialis) (L 4 - S 3 ) innervates the posterior group of muscles of the lower leg, knee and ankle joints, and the skin of the medial surface of the lower leg. On the foot, the lateral and medial plantar nerves depart from it (n. plantarislateralisetmedialis) , which innervate the muscles of the sole of the foot and interosseous muscles ;
peroneal nerve (n. fibulares), innervates the anterior, lateral group of muscles of the lower leg and the skin of the dorsum of the foot and fingers.

It is important to note that the sacral plexus contains many parasympathetic fibers, starting from the lateral horns of the S 2 - S 4 sacral segments of the spinal cord. They form the splanchnic pelvic nerves to innervate the bladder, sigmoid and rectum, internal and external genital organs (Fig. 7).

Coccygeal plexus

Coccygeal plexus (plexuscoccygeus) formed by the anterior branches of the last sacral and coccygeal nerves (S 5 - Co 1 ). This plexus is located on the pelvic surface of the coccygeus muscle and the sacrospinous ligament. From it come thin threads that branch in the skin around the coccyx and anus and innervate the corresponding areas.

Rice. 7. Areas of innervation of the sacral plexus

(I.V. Gaivoronsky., 2009)

Test tasks

1. The obturator nerve is formed from the following plexus

lumbar
shoulder
sacral
cervical

2. The femoral nerve innervates

hip flexors
hip extensors
shin flexors
foot extensors

3. The mixed nerves of the cervical plexus include

phrenic nerve
transverse nerve of the neck
lesser occipital nerve
supraclavicular nerve

4. The brachial plexus is formed by the anterior branches

C 5 - T 1
From 8 - T 1
C 4 - T 2
C 4 - T 1

5. BRANCHES OF THE ULNA NERVE INNERVATE

shoulder flexors
shoulder extensors
flexors of the hand, fingers, skin of the hand
skin of the shoulder and forearm

6. Muscles lower limb innervated from the following plexuses

from the sacral
from the lumbar
simultaneously from the lumbar and sacral
from the lower intercostal nerves

7. THE MEDIA NERVE INNERVIATES

shoulder flexors
flexor muscles of the forearm, hand, skin of the hand
extensor muscles of the forearm
skin of the shoulder and forearm

8. The musculocutaneous nerve is involved in

shoulder extension at the shoulder joint
regulation of skin sensitivity of the forearm
extension of the shoulder at the elbow joint
regulation of skin sensitivity of the shoulder

9. The sciatic nerve arises from the plexus

sacral
lumbar
cervical
shoulder

10. The radial nerve belongs to

anterior brachial plexus
long branches of the cervical plexus
posterior brachial plexus
intercostal nerves

Situational tasks

Task No. 1.

In a patient with a comminuted fracture of the fibula in the area of its upper third, extension of the foot is impossible (picture of a “falling foot”), its lateral edge is lowered, the patient moves by slapping his foot. Skin sensitivity on the lateral side of the leg and dorsum of the foot is impaired.

Name the damaged nerve.

Task No. 2.

The patient has impaired sensory innervation of the skin of the palmar surface of the 5th finger.

Name the damaged nerve.
Give an anatomical basis for its damage.

Task No. 3.

As a result of polio, the patient's motor neurons in the upper lumbar segments of the spinal cord, which participate in the formation of the femoral nerve, were affected.

Name the clinical manifestations characterizing lesions of this nerve.
Give an anatomical basis for its damage.

Task No. 4.

An examination of the patient revealed paralysis of all muscles of the sole of the foot and the inability to stand on the toes.

Name the damaged nerve.
Give an anatomical basis for its damage.

Task No. 5.

During training, a gymnast suffered a dislocation of his shoulder with a downward displacement of the head of the humerus.

Name the damaged nerve.
Indicate the areas of innervation of this nerve.

Task No. 6.

At cervical osteochondrosis Pain in the right forearm and hypochondrium with disruption of the inhalation process is often observed.

Name the damaged nerve.
Indicate which nerves it relates to.
Determine the spinal cord plexuses to which the affected nerve belongs.

Task No. 7.

As a result of the pathological process in the pelvic cavity, the patient has impaired movements in the hip joint (adduction is impossible, supination is difficult), in addition, there is a decrease in the sensitivity of the skin of the medial surface of the thigh.

Name the affected nerve.
Indicate the spinal cord plexuses to which the affected nerve belongs.

Task No. 8.

The patient was admitted to the pulmonary clinic with complaints of difficulty breathing and chest pain.

Identify the affected nerves.
Indicate the segments of the spinal cord from which the affected nerves arise.

Task No. 9.

The patient has a disorder of skin sensitivity in the occipital region of the head.

Indicate damaged spinal nerves.
Indicate the spinal cord plexuses from which the affected nerves arise.

Task No. 10.

Hitting the quadriceps tendon with a hammer causes a knee-jerk reaction. In response, the lower leg is extended.

Indicate the nerve that carries out this reflex.
Indicate the spinal cord plexuses from which the affected nerves arise.

1.2. Functional morphology of cranial nerves

The cranial section of the peripheral nervous system includes 12 pairs of cranial nerves, sensory nodes V, VII, VIII, IX, X pairs, vegetative nodes III, VII, IX, X pairs. Cranial nerves are divided into sensory, motor and mixed. The sensory cranial nerves include: olfactory (I), optic (II) and vestibulocochlear (VIII). Motor cranial nerves: oculomotor (III), trochlear (IV), abducens (VI), accessory (XI), hypoglossal (XII). The mixed cranial nerves include: trigeminal (V), facial (VII), glossopharyngeal (IX), vagus (X).

general characteristics sensory cranial nerves

(I, II, VIII pairs)

The sensory cranial nerves include: olfactory (I), optic (II) and vestibulocochlear (VIII).

Olfactory nerve, (I pair), (n. olfactorius). The first neurons of the olfactory analyzer pathway are located in the mucous membrane of the superior nasal concha. Their processes merge and form approximately 20 olfactory filaments ( filiolfactorii), which through laminacribrosa The ethmoid bones are directed into the cranial cavity. The olfactory nerves end on the neurons of the olfactory bulbs. The conducting path of the olfactory analyzer begins in these structures. It is represented by the olfactory bulbs, olfactory tracts, olfactory triangles, anterior perforated space and transparent partition, hippocampus (Ammon's horn), cingulate, parahippocampal, dentate gyrus, and hook.

Optic nerve (II pair) (n. opticus). It is formed by processes of ganglion cells of the retina. Through canalisopticus is directed into the cranial cavity to the optic chiasm. From the chiasm begin the optic tracts, which contain fibers from the same halves of the retina of both eyes and are the paths of the visual analyzer.

Vestibulocochlear nerve (VIII pair) (n. vestibulocochlearis) . Has two sensitive nodes: g. cochleare in the cochlea rod (receives sound vibrations) and g. vestibulare(perceives gravitational and vibration stimuli) in the bottom of the internal auditory canal. The central processes of the pseudounipolar cells of these nodes leave the cavity of the inner ear through the internal auditory opening and immediately enter the substance of the brain, where they form synaptic contacts with neurons localized in the lateral corners of the rhomboid fossa. Next follows the path of the auditory and statokinetic analyzers.

General characteristics of motor cranial nerves

(III, IV, VI, XI, XII pairs)

The motor cranial nerves include: oculomotor (III pair), trochlear (IV pair), abducens (VI pair), accessory (XI pair), hypoglossal (XII pair).

III pair - oculomotor nerve (n. oculomotorius). Motor fibers begin from the motor nuclei located at the level of the superior colliculus in the midbrain. The autonomic (parasympathetic) nucleus (Yakubovich) occupies a medial position and is located above the cerebral aqueduct. The oculomotor nerve leaves the brain substance in the region of the midbrain peduncles, and through the superior orbital fissure it follows into the orbit. The motor fibers of the oculomotor nerve innervate the superior, inferior, medial rectus, inferior oblique and levator palpebral muscles.

Parasympathetic fibers of the third pair of cranial nerves innervate the ciliary muscle and the sphincter of the pupil (Fig. 8).

IV pair – trochlear nerve ( n. trochlearis) contains only motor fibers. The nuclei of the trochlear nerve are located in the midbrain at the level of the inferior colliculi. The fourth pair of cranial nerves is the only nerve that exits on the dorsal surface of the pons. Enters the orbit through the superior orbital fissure. The trochlear nerve innervates the superior oblique muscle of the eyeball (Fig. 8).

VI pair – abducens nerve (n. abducens) contains only motor fibers. The nucleus of the VI pair of cranial nerves is located in the dorsal part of the pons. It emerges from the substance of the brain between the pons and the medulla oblongata. Enters the orbit through the superior orbital fissure. The abducens nerve innervates the lateral rectus muscle of the eyeball (Fig. 8).

Rice. 8. Scheme of formation and area of innervation of the oculomotor (III pair), block ( IV pair) and outlet ( VI pair) of cranial nerves (A.V. Kondrashev, 2008)

XI pair - accessory nerve ( n. accessorius) contains only motor fibers. The nuclei are located in the medulla oblongata and the upper five segments of the spinal cord. The nerve leaves the substance of the brain in the region of the posterior lateral sulcus of the medulla oblongata. Through the jugular foramen, the accessory nerve leaves the cranial cavity. This nerve innervates the trapezius and sternocleidomastoid muscles (Fig. 9).

Rice. 9. Diagram of the formation and area of innervation of the accessory nerve (XI pair of cranial nerves) (A.V. Kondrashev, 2008)

XII pair - hypoglossal nerve (n. hypoglossus) contains only motor fibers. The motor nucleus of the XII pair of cranial nerves is located in the lower corner of the rhomboid fossa. This nerve leaves the substance of the brain between the pyramid and the olive, and from the cranial cavity through the canal of the hypoglossal nerve. The hypoglossal nerve innervates the proper muscles of the tongue and the muscles located below the hyoid bone (Fig. 10).

Rice. 10. Scheme of formation and area of innervation of the hypoglossal nerve ( XII pair of cranial nerves) (A.V. Kondrashev, 2008)

General characteristics of mixed cranial nerves

(V, VII, IX, X pairs)

The mixed cranial nerves include: trigeminal nerve (V pair), facial nerve (VII pair), glossopharyngeal nerve (IX pair), vagus nerve (X pair).

V pair - trigeminal nerve ( n.trigeminus) refers to mixed nerves, as it contains sensory and motor fibers (Fig. 11). The V pair of cranial nerves contains 4 nuclei located in the midbrain, pons, and medulla oblongata. The motor (masticatory) nucleus is located in the tegmentum of the bridge (nucleus motorius n. trigemini). Three sensitive: 1) pavement in the dorsolateral part of the bridge (nucleussensoriusprincipalisn. trigemini), 2) nucleus of the spinal tract (nucleustractusspinalisn. trigemini), 3) nucleus of the midbrain tract ( nucleusmesencephalicusn. trigemini).

Rice. 11. Branches of the trigeminal nerve (V pair of cranial nerves)

(O. Feitz, 2009)

The motor fibers of the V pair of cranial nerves form a motor root that is smaller in diameter. The sensitive root is formed by the central processes of the pseudounipolar nerve cells of the Gasserian (lunate) ganglion.

The Gasserian node (g. trigeminale) is located on the anterior surface of the pyramid of the temporal bone. The central processes of its cells end on the cells of the mesencephalic, pontine and spinal nuclei of the trigeminal nerve.

The peripheral processes of the pseudounipolar nerve cells of the Gasserian ganglion form 3 branches: the optic nerve is a sensory nerve, the maxillary nerve is a sensory nerve, the mandibular nerve is a mixed nerve, which includes the entire motor root.

Optic nerve (n. Ophthalmicus) leaves the cranial cavity along with the III, IV, VI pairs of cranial nerves through the superior orbital fissure. This branch innervates the skin of the forehead, eyelids, lacrimal gland, and eyeball (Fig. 12).

Rice. 12. Areas of innervation of the optic nerve (first branch of the trigeminal nerve) (O. Feitz, 2009)

Maxillary nerve (n. maxillaris) through the round opening enters the pterygopalatine fossa, from where it exits onto the face through the inferior orbital fissure.

This branch innervates the skin of the lower eyelid, cheek, forehead, nose, upper lip, gum, teeth upper jaw(Fig. 13).

Rice. 13. Areas of innervation of the maxillary nerve (second branch of the trigeminal nerve) (O. Feitz, 2009)

Mandibular nerve (n. mandibularis) contains sensory fibers and the entire motor root. It leaves the cranial cavity through the foramen ovale and is divided into muscular and sensory branches. Muscular branches are directed to the masticatory muscles, sensitive - to the mucous membrane of the cheek, tongue, lower teeth, skin of the auricle, parotid salivary gland(Fig. 14).

Rice. 14. Areas of innervation of the mandibular nerve (third branch of the trigeminal nerve) (O. Feitz, 2009)

VII pair - facial nerve (n. facialis) refers to mixed nerves as it contains sensory, motor and autonomic fibers (Fig. 15).

Rice. 15 . Diagram of the formation and area of innervation of the facial nerve (VII pair of cranial nerves) (O. Feits, 2009)

The VII pair of cranial nerves contains 3 nuclei, which are located in the pons and medulla oblongata:

motor – (nucleusmotoriusn. faciali) located in the bridge at the level of the facial tubercle;
(nucleus tractus solitarii)(common with IX and X pairs);
vegetative - superior salivary nucleus (nucleus salivatorius superior) located in the bridge at the level of the reticular formation.

VII pair leaves the brain substance along the posterior edge of the pons. Together with the vestibulocochlear nerve, it enters the internal auditory canal and leaves the cranial cavity through the stylomastoid foramen.

In the submandibular fossa, the facial nerve is divided into motor (motor) and secretory branches.

The motor branches of the facial nerve innervate the facial muscles, the muscles of the calvarium, the subcutaneous muscle of the neck, the stylohyoid and digastric muscles.

The secretory part is called the intermediate nerve (n. intermedius). The sensitive ganglion of the intermediate nerve is called the ganglion geniculi and lies in the facial canal of the temporal bone.

Peripheral processes extending from the sensitive ganglion of the intermediate nerve are part of the chorda tympani (chordatympani) innervate the mucous membrane of the tongue. The chorda tympani also contains autonomic fibers that innervate the submandibular and sublingual salivary glands.

IX pair - glossopharyngeal nerve ( n.glossopharyngeus) refers to mixed nerves, as it contains sensory, motor and autonomic fibers (Fig. 16).

Rice. 16. Diagram of the formation and area of innervation of the glossopharyngeal nerve (IX pair of cranial nerves) (O. Feits, 2009)

The glossopharyngeal nerve has 3 nuclei, which are localized in the medulla oblongata.

motor – double (nucleusAmbiguus) common with X pair;
sensitive – nucleus of the solitary tract (nucleus tractus solitarii)(common with VII and X pairs);
(nucleus salivatoriusinferior) .

The glossopharyngeal nerve exits the medulla oblongata through the posterior lateral sulcus and leaves the cranial cavity through the jugular foramen. In this foramen, the nerve has its first extension - the superior sensory node (g. superius), and upon exiting the jugular foramen - the lower sensory node (g. inferius).

The glossopharyngeal nerve contains motor (motor), sensory (sensory) and parasympathetic fibers.

The motor fibers of the glossopharyngeal nerve are axons of the cells of the nucleus ambiguus. They innervate the stylopharyngeal muscle, as well as the pharyngeal constrictors and muscles of the soft palate.

Fibers of general sensitivity begin from the neurons of both nodes, fibers of taste sensitivity - from the lower node. Peripheral processes extending from the sensitive nodes innervate the mucous membrane of the palatine tonsil, palatine arches, pharynx, posterior third of the tongue, as well as the tympanic cavity.

Autonomic fibers start from the neurons of the inferior salivary nucleus and reach the ear node (g.oticum), where they switch to its neurons. Postganglionic branches innervate the parotid gland.

X pair - the vagus nerve (n. vagus) belongs to the mixed nerves, as it contains sensory, motor and autonomic fibers (Fig. 17).

Rice. 17. Diagram of the formation and area of innervation of the vagus nerve (X pair of cranial nerves) (O. Feits, 2009)

The vagus nerve is formed by the processes of neurons of 3 nuclei located in the medulla oblongata:

motor – double (nucleusAmbiguus), common with IX pair;
sensitive – nucleus of the solitary tract (nucleus tractus solitarii)(common with VII and IX pairs);
vegetative - inferior salivary nucleus (nucleus salivatoriusinferior.

The vagus nerve leaves the medulla oblongata behind the olive through numerous roots that merge into a common trunk, which exits the skull through the jugular foramen. The X pair shares sensory nodes with the glossopharyngeal nerve - superior and inferior.

The vagus nerve has several sections: head, cervical, thoracic, abdominal. From these sections branch branches that innervate certain zones.

In the cephalic region, the vagus nerve gives off the following branches:

the meningeal branch innervates the dura mater;
The auricular branch innervates the skin of the auricle and the external auditory canal.

Branches of the vagus nerve cervical spine:

pharyngeal branches innervate the posterior wall of the pharynx;
the superior laryngeal nerve innervates the ligaments, cartilages and muscles of the larynx, as well as the thyroid gland;
The superior and inferior cardiac branches innervate the membranes of the heart.

In the thoracic region, the vagus nerve gives off the following branches: the recurrent laryngeal nerve innervates all the muscles of the larynx;

esophageal branches - for the thoracic esophagus;
tracheal branches - to thoracic region trachea;
bronchial branches - innervate the bronchi;
pericardial innervate the pericardium;
thoracic cardiac branches - carry out parasympathetic innervation of the heart.

The branches of the vagus nerve in the abdominal region are:

anterior gastric branches for the anterior surface of the stomach;
posterior gastric branches for the posterior surface of the stomach;
the celiac branches participate in the formation of the celiac plexus, which innervates the abdominal organs;
hepatic branches are part of the hepatic plexus, which innervates the liver and gall bladder;
the renal branches form the renal plexus.

Test tasks
Choose one correct answer.

1. The optic nerve is formed from cell processes

ganglion layer
layer of rods and cones
inner nuclear layer
outer mesh layer

2. Accessory nerve refers to

sensory cranial nerves
mixed cranial nerves
motor cranial nerves
cervical plexus

3. A nerve exits behind the olive medulla oblongata

trigeminal
wandering
sublingual
facial

4. The lateral rectus muscle of the eyeball is innervated by the next nerve

oculomotor
trigeminal
diverting
block

5. The inferior salivary nucleus is involved in the formation of the nerve

facial
glossopharyngeal
wandering
additional

6. The nucleus of the solitary tract is localized in

diencephalon
medulla oblongata
midbrain
bridge

7. The facial nerve leaves the cranial cavity through

foramen ovale
stylomastoid foramen
greater palatine canal
foramen spinosum

8. The optic nerve is a branch of the NERVE

oculomotor
facial
trigeminal
wandering

9. Parasympathetic innervation of the sublingual salivary gland is carried out by the branches of the next nerve

facial
glossopharyngeal
wandering
trigeminal

10. The glossopharyngeal nerve leaves the cranial cavity through

superior orbital fissure
foramen ovale
round hole
jugular foramen

Situational tasks

Task No. 1.

In an ophthalmology clinic, during a visual examination of the patient, the ophthalmologist revealed the following symptoms: strabismus, impaired binocular vision, ptosis, mydriasis, paralysis of accommodation.

Attribute it to the group of cranial nerves.

Task No. 2.

At an appointment with a neurologist, the patient complains of excruciating short-term pain (painful paroxysms) occurring on the skin of the face, mucous membrane oral cavity, teeth, tongue. These complaints are combined with hyperemia and sensitivity disorder of the facial skin, profuse salivation, increased sweating in certain areas of the maxillofacial area, limited chewing movements (the jaw hangs down, the patient has difficulty closing the mouth), speech impairment and severe neuropsychic stress.

Assume the affected nerve.
Clarify its branches.
Indicate the zones of its innervation.

Task No. 3.

In the neurological clinic, the patient complains of facial distortion at rest and skewing to the healthy side during facial movements, difficulty eating (solid food remains between the cheek and gum, and liquid food pours out through the drooping corner of the mouth on the affected side), pain in the brow ridge , auricle and mastoid process, as well as in the chin area, impaired sensitivity of the facial skin, especially in the temple, lips and nose, decreased tear production, dry mouth, impaired taste sensitivity.

Specify the affected cranial nerve.

Task No. 4.

After a course of treatment with the antibiotic gentamicin, the child developed the following symptoms: hypoacusia (decreased hearing), horizontal nystagmus (spontaneous combined movements of both eyeballs), dizziness, ataxia (staggering gait).

Name the affected cranial nerve.
Clarify its nuclei and location.

Task No. 5.

An examination of a patient with a fracture of the base of the skull revealed: loss of taste and general sensitivity of the mucous membrane of the posterior third of the tongue, impaired sensitivity in the pharynx, pharynx, and some swallowing disorders.

Assume affected nerves.
Determine their nuclei and location.

Task No. 6.

In a young girl, as a result of the development of neuroglioblastoma, compression of blood vessels and nerves in the area of the jugular foramen was revealed, which was accompanied by impaired swallowing, paresis of the soft palate, constant choking, coughing, hoarseness and dysphonia as a result of paresis of the vocal cords.

Name the affected cranial nerve.
Clarify its motor, sensory and autonomic functions

kernels.
Task No. 7.

Upon visual examination, the patient’s protruding tongue deviates towards the lesion, there is no impairment of taste or tactile sensitivity in the anterior third of the tongue, and there is no impairment of salivary function.

Name the affected cranial nerve.
Characterize the places where this nerve exits the brain substance, the projection of the nuclei and the area of innervation.

Task No. 8.

Upon visual examination, the patient's shoulder is lowered, the scapula is displaced outward, he cannot shrug his shoulder, raise his arm, or turn his head to the healthy side.