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Not located in the nuclei of the medulla oblongata. Medulla oblongata

The medulla oblongata is a direct continuation of the spinal cord. Its lower border is the exit point of the first pair of spinal nerves. The length of the medulla oblongata is about 25 mm. The cranial nerves from the IX to the XII pairs depart from the medulla oblongata. In the medulla oblongata there is a cavity (a continuation of the spinal canal) - the fourth cerebral ventricle, filled with cerebrospinal fluid.

Functions medulla oblongata: conductive and reflex, some also distinguish sensory.

Sensory function. The medulla oblongata regulates a number of sensory functions: reception of skin sensitivity of the face - in the sensory nucleus of the trigeminal nerve; primary analysis of taste reception - in the nucleus of the glossopharyngeal nerve; reception of auditory stimuli - in the nucleus of the cochlear nerve; reception of vestibular irritations - in the superior vestibular nucleus. In the postero-superior parts of the medulla oblongata there are pathways of cutaneous, deep, visceral sensitivity, some of which are switched here to the second neuron (gracilis and cuneate nuclei). At the level of the medulla oblongata, the listed sensory functions implement a primary analysis of the strength and quality of irritation, then the processed information is transmitted to the subcortical structures to determine the biological significance of this irritation.

Conductor function: Ascending and descending nerve tracts pass through the medulla oblongata, connecting the brain and spinal cord.

In the medulla oblongata there are olives connected to the spinal cord, the extrapyramidal system and the cerebellum - these are the thin and wedge-shaped nuclei of proprioceptive sensitivity (Gaull and Burdach nuclei). Here are the intersections of the descending pyramidal tracts and the ascending tracts formed by the thin and wedge-shaped fascicles (Gaull and Burdach), the reticular formation.

Rice. 9 Medulla oblongata:

1 - olivocerebellar tract;

2 - olive kernel;

3 - olive kernel gate;

5 - pyramidal tract;

6 - hypoglossal nerve;

7 - pyramid;

8 - anterior lateral groove;

9 - accessory nerve

The nuclei of the medulla oblongata include the nuclei of the cranial nerves (from VIII to XII pairs) and switching nuclei:

Cranial nerve nuclei include:

Motor nuclei XII, XI, X;

Vagal nuclei (autonomic, sensory nucleus of the solitary tract and reciprocal – motor nucleus of the pharynx and larynx);

Nuclei of the glossopharyngeal nerve (IX) (motor nucleus, sensory nucleus - taste of the posterior third of the tongue) and autonomic nucleus (salivary glands);

Nuclei of the vestibulocochlear nerve (VIII) (cochlear nuclei and vestibular nuclei - medial Schwalbe, lateral Deiters, superior Bechterew).

Switching Cores include:

Gaulle and Burdakh - to the thalamus;

Reticular formation (from the cortex and subcortical nuclei - to the spinal cord);

Olivary nuclei - from the cortex and subcortical nuclei and cerebellum - to the spinal cord, and from the spinal cord - to the cerebellum, thalamus and cortex; from the auditory nuclei - to the midbrain and quadrigemina.

Reflex function: The centers of many important reflexes for human life are located in the medulla oblongata.

The medulla oblongata, due to its nuclear formations and reticular formation, is involved in the implementation of vegetative, somatic, gustatory, auditory, and vestibular reflexes. A feature of the medulla oblongata is that its nuclei, being excited sequentially, ensure the execution of complex reflexes that require the sequential activation of different muscle groups, which is observed, for example, when swallowing.

Centers of the medulla oblongata:

Autonomic (vital) centers

    Respiratory (center of inhalation and exhalation);

    Cardiovascular (maintains optimal lumen of arterial vessels, ensuring normal blood pressure and cardiac activity);

Most of the vegetative reflexes of the medulla oblongata are realized through the nuclei of the vagus nerve located in it, which receive information about the state of activity of the heart, blood vessels, digestive tract, lungs, digestive glands, etc. In response to this information, the nuclei organize motor and secretory reactions of the visceral organs.

Excitation of the vagus nerve nuclei causes increased contraction of the smooth muscles of the stomach, intestines, and gallbladder and at the same time relaxation of the sphincters of these organs. At the same time, the work of the heart slows down and weakens, and the lumen of the bronchi narrows.

The activity of the vagus nerve nuclei is also manifested in increased secretion of the bronchial, gastric, intestinal glands, and in the stimulation of the pancreas and secretory cells of the liver.

Defense reflex centers

    Tears;

These reflexes are realized due to the fact that information about irritation of the receptors of the mucous membrane of the eye, oral cavity, larynx, nasopharynx through the sensitive branches of the trigeminal and glossopharyngeal nerves enters the nuclei of the medulla oblongata, from here comes the command to the motor nuclei of the trigeminal, vagus, facial, glossopharyngeal, accessory or hypoglossal nerves, as a result, one or another protective reflex is realized.

Eating Behavior Reflex Centers:

    Salivation (the parasympathetic part ensures increased general secretion, and the sympathetic part ensures increased protein secretion of the salivary glands);

  2. Swallowing;

Posture reflex centers.

These reflexes are formed due to afferentation from the receptors of the vestibule of the cochlea and semicircular canals to the superior vestibular nucleus; from here, processed information assessing the need to change posture is sent to the lateral and medial vestibular nuclei. These nuclei are involved in determining which muscular systems and segments of the spinal cord should take part in changing posture, therefore, from the neurons of the medial and lateral nuclei along the vestibulospinal tract, the signal arrives to the anterior horns of the corresponding segments of the spinal cord innervating the muscles that participate in changing posture in necessary at the moment.

Changes in posture are carried out due to static and statokinetic reflexes. Static reflexes regulate the tone of skeletal muscles in order to maintain a certain body position. Statokinetic reflexes of the medulla oblongata provide redistribution of the tone of the trunk muscles to organize a posture corresponding to the moment of rectilinear or rotational movement.

Symptoms of damage. Damage to the left or right half of the medulla oblongata above the intersection of the ascending pathways of proprioceptive sensitivity causes disturbances in the sensitivity and functioning of the muscles of the face and head on the side of the damage. At the same time, on the opposite side to the side of the injury, disorders of skin sensitivity and motor paralysis of the trunk and limbs are observed. This is explained by the fact that the ascending and descending pathways from the spinal cord and into the spinal cord intersect, and the nuclei of the cranial nerves innervate their half of the head, i.e., the cranial nerves do not intersect.

Being an integral part of the trunk, located on the border of the spinal cord and the pons, the medulla oblongata is a cluster of vital centers of the body. This anatomical formation includes elevations in the form of ridges, which are called pyramids.

This name didn't just appear out of nowhere. The shape of the pyramids is perfect, a symbol of eternity. The pyramids are no more than 3 cm long, but our life is concentrated in these anatomical formations. On the sides of the pyramids there are olive trees, and also outward the rear pillars.

This is a concentration of pathways - sensitive from the periphery to the cerebral cortex, motor from the center to the arms, legs, and internal organs.

The pathways of the pyramids include motor portions of nerves that partially intersect.

The crossed fibers are called the lateral pyramidal tract. The remaining fibers in the form of the anterior path do not lie on their side for long. At the level of the upper cervical segments of the spinal cord, these motor neurons also extend to the contralateral side. This explains the occurrence of motor disorders on the other side of the pathological focus.

Only higher mammals have pyramids, since they are necessary for upright walking and higher nervous activity. Thanks to the presence of pyramids, a person carries out the commands he hears, conscious thinking appears, and the ability to combine a set of small movements into combined motor skills.

Sensitivity of the medulla oblongata

The medulla oblongata has 3 sensory nuclei: the gracilis, the sphenoid, and the trigeminal nerve. The first two nuclei provide proprioceptive sensitivity. The function of proprioception is to control the position of the body in space.

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All internal organs, muscles, joints, and ligaments contain receptors that send signals to the brain about the position of the body in space, blood flow to organs, and flexion and extension of limbs. Up to the medulla oblongata, the signal travels along its side, and above the thin, wedge-shaped nuclei of Gaulle and Burdach, it crosses and goes to the opposite side.

In order to determine whether deep sensitivity is suffering or not, the patient is asked to close his eyes. Then bend or straighten any finger on the leg or hand. The patient must name which finger is being used and what is being done.

The sensory spinal nucleus of the trigeminal nerve contains fibers of only two branches of the trigeminal nerve - the optic and maxillary. The mandibular branch contains only motor fibers. This knowledge helps in the differential diagnosis of supernuclear and nuclear lesions.

Vital centers


The medulla oblongata contains centers for breathing, swallowing, coughing, cardiovascular activity and other anatomical formations important for the life of the body.

From the respiratory center, information enters the spinal cord, which provides movement to the respiratory muscles. This allows you to make the act of breathing rhythmic. The process that alternates inhalation and exhalation is controlled in the medulla oblongata. And it is regulated by impulses coming from the interoreceptors of the lung tissue, pleura, aorta, intercostal muscles, respiratory tract, skin receptor apparatus, and muscles.

For example, at low ambient temperatures, skin thermoreceptors send a signal to the medulla oblongata, which increases blood pressure, inspiratory volume, and decreases the frequency of respiratory movements.

This set of regulatory influences on cardiovascular respiratory activity is provided by the spinal cord, phrenic, intercostal nerves, skin, and mucous membranes. The medulla oblongata and cerebral cortex, receiving information from the periphery, regulate the activity of the vasomotor and other vital centers.

Participation of the medulla oblongata in autonomic innervation

The medulla oblongata performs the functions of control over the endocrine and exocrine glands due to the presence in it of nuclei of salivation, vagus, regulators of digestion, bile secretion, immunity, and cardiovascular activity.

The vegetative part of the medulla oblongata is closely interconnected with the hypothalamus and therefore takes part in the formation of feelings of hunger, thirst, and controls appetite.

The structure and functions of the medulla oblongata explain such phenomena as salivation in response to the entry of chemicals into the oral cavity, to the sight and smell of food.

The release of saliva at the sight of food is a conditioned reflex that is formed on the basis of life experience on the basis of an innate reflex.

Mechano-, thermo-, temperature and other types of receptors collect information from all internal organs and the gastrointestinal tract. Part of the information enters the medulla oblongata, the secretion of gastric juice and bile secretion begin, which are necessary for successful digestion.

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A small fraction of impulses is sent to the brain region that controls digestion. From there, the body receives a command about what conditions for eating food will suit it and what the quality of the food consumed should be.

Nuclear structure of the medulla oblongata


For a brief description and determination of the level of damage, it is necessary to know about the symptoms that develop during pathological processes in the posterior cranial fossa. The medulla oblongata has a specific structure and functions determined by the location of the nuclei of 5, 8, 9, 10, 11, 12 pairs of nerves.

Nuclear damage to the trigeminal nerve is manifested by a violation of pain and temperature types of sensitivity. The sensation of a light touch does not suffer. This is most typical for syringomyelia.

With nuclear damage to the vestibulocochlear nerve, dizziness and nystagmus appear, and the friendly rotation of the eyes in the direction opposite to the head suffers.

The glossopharyngeal and vagus nerves have common nuclei. The functional state of these cranial nerves is checked together. They innervate the larynx, pharynx, posterior third of the tongue, internal organs of the abdominal and thoracic cavities, tonsils, hearing organs, dura mater, and heart.

The medulla oblongata regulates the vital functions of the body, so bilateral damage to these nerves in combination with the sublingual may be incompatible with life, since bulbar syndrome develops.

The latter is characterized by impaired swallowing, voice, breathing, and disorders of cardiovascular activity. This situation develops with tumors, amyotrophic lateral sclerosis, pseudorabies, polio, and diphtheria.

The medulla oblongata is a continuation of the spinal cord, its origin is the upper border of the first cervical vertebra (C 1). In shape, it resembles an inverted cone with a truncated top and has relatively small dimensions: average length 25 mm, width at the base 22 mm, thickness 14 mm. The medulla oblongata weighs on average about 6 grams.

Development

During ontogenesis, the medulla oblongata develops from the neural tube. In the fifth week of embryonic development, the three-brain vesicle stage occurs, where it originates from the rhombencephalon. The morphological features of the relief of the medulla oblongata are caused by metamorphoses during the process of organogenesis. The lateral walls of the neural tube become thicker, and the dorsal wall, on the contrary, becomes thinner and remains only in the form of a thin plate with a layer of ependymal epithelium and the choroid of the fourth ventricle adjacent to it on the outside.

Structure

Now let's talk about the morphological component. The medulla oblongata is divided into ventral, dorsal and lateral sides, as well as white and gray matter. Let's start by looking at the topography of the sides and the important anatomical formations that are located there.

The dorsal surface is the most variable in its structure. In the center of it there is a posterior median groove, sulcus medianus posterior. On the sides of it there are two bundles: the thin bundle of Gaulle and the wedge-shaped bundle of Burdach - these are continuations of the posterior cords of the spinal cord. On both sides, lateral to the sphenoid fasciculus, there are lateral cords, which form small thickenings in the middle of the medulla oblongata; they are called the inferior cerebellar peduncles, pedunculus cerebellaris inferior. Between these legs a triangle-shaped area is formed - this is the lower half of the diamond-shaped fossa. It is important to note that this structure is distinguished only anatomically.

Now let's move on to the side surfaces. Lateral to the pyramids is the anterior lateral groove, sulcus anteriolateralis, which is also a continuation of the groove of the same name on the spinal cord. Next to it are olive trees. Behind the olives there is a posterior lateral groove, sulcus posteriolateralis, which has no analogues on the spinal cord. The roots of the cranial nerves will emerge from it: accessory (n. accessorius XI pair), vagus (n. vagus X pair), glossopharyngeus (n. glossopharyngeus IX pair).

And finally, on the ventral side there are the pyramids of the medulla oblongata, pyramides medullae oblongatae. They are located on the sides of the anterior median fissure, fissura mediana anterior, which is a continuation of the groove of the same name on the spinal cord. At the border with the spinal cord, the fibers of the pyramids intersect, forming the decussation of the pyramids, decussatio pyramidum.

Cores

Now let's talk about the internal structure of the medulla oblongata. It consists of gray and white matter. The gray matter is represented by nuclei, and the white matter by longitudinally directed nerve fibers, which subsequently form descending pathways. But first things first.

We will begin our study of the internal structure with the gray matter. It differs in shape from that in the spinal cord: here it is represented exclusively by nuclei. Traditionally they are divided into four groups:

First group: thin and wedge-shaped nuclei. They are located in the tubercles of the same name and represent the terminal neurons of the fibers of the thin and cuneate fasciculi. An important feature here is the movement of the fibers. The main part of the axons of these nuclei is directed ventrally in a single bundle, and then to the opposite side and upward. In the midline region, these fibers form the decussation of the medial loops, decussatio lemniscorum medialium. The end of the medial loop is located on the nuclei of the thalamus, which determines the second name for the Gaulle bundle - the bulbar-thalamic tract, tr. bulbothalamicus. The remaining axons make up another pathway - the bulbar-cerebellar, tr. bulbocerebellaris. These fibers run anteriorly, emerge on the ventral surface of the medulla oblongata near the anterior median fissure, go around the pyramids and enter it as part of the lower cerebellar peduncles.

The second group of kernels are olive kernels. From the cerebral cortex and from the red nuclei of the midbrain, nerve fibers go to the olive nuclei. Here, as in the previous group of nuclei, the path goes contralaterally, that is, most of the axons move to the opposite side and enter the cerebellum as part of its inferior peduncle, forming the olivo-cerebellar tract, tr. olivocerebellaris. The remaining part of the axons will form the descending olivospinal tract, tr. olivospinalis.

Slightly dorsal to the olive is the third group of nuclei - the nuclei of the reticular formation, nuclei formation reticularis. It is known that the medulla oblongata is a rather important part of the central nervous system, since it houses the nerve centers of complex reflex acts of breathing, heartbeat, and the center for regulating vascular and muscle tone. Representatives of these centers are the large nuclei of the reticular formation. There are also so-called nonspecific nuclei, which are interneurons of the segmental apparatus of the brain stem.

The fourth group of nuclei is represented by the nuclei of cranial nerves IX-XII pairs. All of them are located on the posterior surface of the medulla oblongata, closer to the cavity of the fourth ventricle. Let's start with the XII pair - the hypoglossal nerve, its nuclei lie in the region of the hypoglossal triangle, in the medial part of the lower angle of the rhomboid fossa. Rostral (higher) lies the nucleus of the accessory nerve, n. accessorius. In the medulla oblongata, on the dorsal surface, within the triangle of the vagus nerve, a small area is distinguished - the gray wing, ala cinerea. It contains the projection of the autonomic parasympathetic dorsal nucleus of the vagus nerve, nucleus dorsalos nervi vagi. Even higher than the dorsal nucleus of the vagus nerve lies the autonomic parasympathetic nucleus of pair IX, n. glossopharyngeus – lower salivary nucleus, nucleus salivatorius inferior. Lateral to the autonomic nuclei, which we have just examined, lies an elongated structure containing sensory nuclei for the X and IX pairs of cranial nerves - this is the nucleus of the solitary tract, nuclei tractus solitarii. An interesting point follows: most textbooks say that the double nucleus, nucleus ambiguous, is common to two pairs of cranial nerves - pairs X and IX, but this is not entirely accurate. There is information that it is common to three pairs, thus, the nucleus ambiguous is also the motor nucleus for pair XI, n. accessories. It has a projection in the region of the posterior median sulcus, in the lower part of the rhomboid fossa. This concludes our consideration of gray matter and moves on to white matter.

The white matter of the medulla oblongata consists of nerve fibers in a longitudinal direction. These fibers are divided into two types: afferent, carrying information to the nervous structures of the central nervous system (ascending) and afferent, carrying information to the periphery, to the working organs and tissues (descending).

The ascending fibers predominantly come from the spinal cord. The bundles of Gaulle and Burdach, already known to us, which are located on the sides of the posterior median sulcus, end on the neurons of the nuclei of the same name and form the ascending tracts: bulbo-thalamic and bulbo-cerebellar. Closer to the lateral surface lie the anterior and posterior spinocerebellar tracts: Gowers and Flexig bundles. The first goes laterally and enters the cerebellum as part of its inferior peduncle, and the ventral Gowers bundle, which follows contralaterally (crosses over), bypassing the thalamus, continues into the pons. Medial to Govers' bundle lies the spinothalamic tract, tr. spinothalamicus, which has a second name - lemniscus spinalis, spinal loop. It unites the fibers of the tracts of the same name, which run along the sides and in front of the spinal cord.

The bulk of the paths are fibers going down. Descending fibers are tracts that originate from various motor nuclei of the brain.

The descending tracts are divided into pyramidal and extrapyramidal, and the latter, in turn, into old and new. The pyramidal and old extrapyramidal tracts pass through the medulla oblongata. The first group of pathways includes: corticospinal, tr. corticospinalis, and subsequently - tr. corticospinalis lateralis et anterior. The largest descending tract is the corticospinal tract, tr. corticospinalis lies on the ventral surface of the medulla oblongata. Before entering it, it goes along its side, and then crosses and goes into the lateral cord of the spinal cord under a different name - tr. corticospinalis lateralis. A small part of the fibers that entered the chiasm continue their path in the anterior funiculus, forming the anterior corticospinal tract, tr. corticospinalis anterior.

On the dorsal surface there are two bundles that contain the pathways of the autonomic nervous system: the posterior and medial longitudinal bundles, fasciculus longitudinalis posterior et medialis. The medial longitudinal fasciculus is an important associative pathway that connects the nuclei of the nerves of the eye muscles with each other, which causes the closure of the reflex of combined rotation of the head and eyes towards sound at the level of the medulla oblongata.

The old extrapyramidal tracts passing through the medulla oblongata include: roof-spinal tract, tr. tectospinalis, reticular spinal tract, tr. reticulospinalis, vestibulospinal tract, tr. vestibulospinalis, red nucleus-spinal tract, tr.rubrospinalis. Roof-spinal tract, tr. tectospinalis, lies in front of the medial bundle. Dorsal to the pyramids is the reticular spinal tract, tr. reticulospinalis. More lateral lies the vestibulospinal tract, tr. vestibulospinalis, and medial to the spinothalamic tract is the red nuclear spinal tract, tr.rubrospinalis. The functional anatomy of these pathways determines the performance of complex reflex acts, for example: rapid motor reactions in response to unexpected stimuli or may participate in the inhibition of the activity of motor neurons of the spinal cord.

This concludes our consideration of the main pathways passing through the medulla oblongata. There are also tracts connecting the sensory nuclei of the cranial nerves (IX and X pairs) with the integration centers of the cerebrum - these are the nuclear-thalamic tracts, tr. nucleothalamicus and nuclear-cerebellar, tr. nucleocerebellaris. Together, they will provide general sensitivity in the head area and are responsible for receiving information from interoceptors.

Functions

After a detailed study of all the important structures of the medulla oblongata, namely its morphological components and transit pathways, we can conclude about the main functions of the medulla oblongata:

1. Sensory – perception of afferent influences from receptors and their processing

2. Conductive - conduction of nerve impulses through the medulla oblongata to other parts of the central nervous system and to effector structures

3. Reflex – important vital reflexes are closed at the level of the medulla oblongata: organization and regulation of breathing and blood circulation, maintaining posture and protective reflexes (coughing, sneezing, vomiting)

4. Integrative – the neurons of the medulla oblongata are programmed with algorithms for complex regulatory processes that require interaction with other centers in other parts of the nervous system.

Medulla oblongata is located in the lower half of the brain stem and connects to the spinal cord, being, as it were, its continuation. It is the most posterior part of the brain. The shape of the medulla oblongata resembles an onion or cone. In this case, its thick part is directed upward towards the hindbrain, and the narrow part downwards towards the spinal cord. The longitudinal length of the medulla oblongata is approximately 30-32 mm, its transverse size is about 15 mm, and its anteroposterior size is about 10 mm.

The place where the first pair of cervical nerve roots exits is considered the border of the spinal cord and medulla oblongata. The bulbar-pontine groove on the ventral side is the upper border of the medulla oblongata. The stria medullaris (auditory grooves of the medulla oblongata) represent the upper border of the medulla oblongata from the dorsal side. The medulla oblongata is limited from the spinal cord on the ventral side by the crosshairs of the pyramids. There is no clear boundary of the medulla oblongata on the dorsal side, and the boundary is considered to be the place where the spinal roots emerge. At the border of the medulla oblongata and the pons there is a transverse groove that separates these two structures along with the medullary stripes.

On the outer ventral side of the medulla oblongata there are pyramids in which the corticospinal tract and olives pass, containing the nuclei of the inferior olive, which are responsible for balance. On the dorsal side of the medulla oblongata there are the wedge-shaped and thin bundles, which end in the tubercles of the wedge-shaped and thin nuclei. Also on the dorsal side is the lower part of the rhomboid fossa, which is the bottom of the fourth ventricle and the lower cerebellar peduncles. The posterior choroid plexus is located in the same place.

Contains many nuclei that are involved in many motor and sensory functions. The medulla contains centers responsible for the functioning of the heart (heart center) and the respiratory center. Through this part of the brain, gag and vasomotor reflexes are controlled, as well as autonomic functions of the body, such as breathing, coughing, blood pressure, and the frequency of contractions of the heart muscle.

The formation of rhombomeres Rh8-Rh4 occurs in the medulla oblongata.

Ascending as well as descending pathways in the medulla oblongata go from the left to the right side and are inherited from the right.

The medulla oblongata includes:

  • glossopharyngeal nerve
  • part of the fourth ventricle
  • accessory nerve
  • vagus nerve
  • hypoglossal nerve
  • part of the vestibulocochlear nerve

Lesions and injuries to the medulla oblongata usually always lead to death due to its location.

Functions performed

The medulla oblongata is responsible for certain functions of the autonomic nervous system, such as:

  • Breathing controls the level of oxygen in the blood by sending signals to the intercostal muscles, increasing the rate of their contraction to saturate the blood with oxygen.
  • Reflex functions. This may include sneezing, coughing, swallowing, chewing, and vomiting.
  • Cardiac activity. Through sympathetic excitation, cardiac activity increases, and parasympathetic inhibition of cardiac activity also occurs. In addition, blood pressure is controlled through vasodilation and vasoconstriction.

The medulla oblongata is a part of the central nervous system, also called the bulbus, bulbus or medullaoblongata in Latin. Located between the dorsal region, the bridge and, it is part of the head trunk. Performs many important functions: regulation of breathing, blood circulation, digestion. It is the oldest formation of the central nervous system. Its defeat often leads to death, since vital functions are switched off.

Location and anatomy of the medulla oblongata

The posterior part of the central nervous system is where the medulla oblongata is located. From below it passes into the dorsal, and from above it is adjacent to the bridge. The cavity of the fourth ventricle, filled with fluid (cerebrospinal fluid), separates the bulbus from the cerebellum. It ends approximately where the head meets the neck, that is, its lower border is located at the level of the occipital inlet (hole).

The anatomy of the medulla oblongata is similar to the spinal and cephalic portions of the central nervous system. The bulb consists of white and gray matter, i.e. pathways and nuclei, respectively. It has formations (pyramids) that control motor function and pass into the anterior dorsal pathways.

To the side of the pyramids are olive trees - oval formations separated by a groove. On the posterior surface of the medulla oblongata there are median, intermediate and lateral borders. Posteriorly, cranial fibers of the ninth, tenth and eleventh pairs emerge from the lateral border.

The bulbus of the central nervous system consists of the following gray matter formations:

  1. Olive nucleus, which has connections with the dentate nucleus of the cerebellum. Provides balance.
  2. The reticular formation is a switch that integrates various parts of the central nervous system with each other, ensuring the coordinated functioning of the nuclei.
  3. Vasomotor and respiratory centers.
  4. Nuclei of the glossopharyngeal, vagus, accessory and hypoglossal nerve fibers.

White matter (nerve fibers of the medulla oblongata) provides conductive function and connects the head part of the central nervous system with the spinal part. There are long and short fibers. The pyramidal tracts and the wedge-shaped and thin fasciculus tracts are formed by long conducting fibers.

Functions of the medulla oblongata

The bulbus, as part of the trunk of the central nervous system, is responsible for the regulation of blood pressure and the work of the respiratory muscles. These functions of the medulla oblongata are vital for humans. Therefore, its defeat during injuries and other injuries often leads to death.

Main functions:

  1. Regulation of blood circulation and breathing.
  2. Presence of sneezing and coughing reflexes.
  3. The nucleus of the glossopharyngeal nerve provides swallowing.
  4. The vagus nerve has autonomic fibers that influence the functioning of the heart and digestive system.
  5. Balance is ensured by communication with the cerebellum.

Breathing is regulated through the coordinated work of the inspiratory (responsible for inhalation) and expiratory (responsible for exhalation) departments. Sometimes the respiratory center is suppressed by shock, trauma, strokes, poisoning, and metabolic disorders. It is also suppressed during hyperventilation (increased oxygen levels in the blood). The nucleus of the 10th pair of cranial nerves is also involved in breathing.

Blood circulation is regulated by the work of the vagus nerve nucleus, which affects both cardiac activity and vascular tone. This center receives information from the heart, digestive system and other parts of the human body. The tenth pair of nerves emanating from it reduces the heart rate.

The vagus nerve enhances the functioning of the gastrointestinal tract. Stimulates the release of hydrochloric acid, pancreatic enzymes, accelerates peristalsis of the large intestine. Its sensitive fibers come from the pharynx and eardrum. Motor fibers ensure coordination of swallowing processes, in which the muscles of the pharynx and soft palate participate.

The glossopharyngeal nerves, the ninth pair, ensure the act of swallowing, pushing the bolus of food from the oral cavity into the pharynx, then the esophagus.

The hypoglossal nerve has motor fibers that regulate the functioning of the tongue muscles. Provides sucking, licking, swallowing, articulation (speech).

Symptoms of bulbus damage

Sometimes as a result of injuries, intoxications, metabolic diseases, hemorrhages, ischemia, shock states, activity medullaoblongata is disrupted, leading to bulbar syndrome. Main causes of pathology:

  1. Strokes (hemorrhages).
  2. Syringomyelia (presence of cavities).
  3. Porphyria.
  4. Botulism.
  5. Dislocation syndrome in injuries, hematomas.
  6. Diabetes mellitus, ketoacidosis.
  7. Effect of antipsychotic drugs.

It is important to find out: structure, functions, symptoms in pathological conditions.

What they lead to: treatment, diagnosis, prevention.

Note: and what the violation of its functions leads to.

Symptoms of medulla oblongata damage include:

  1. Circulatory disorders: bradycardia, decreased blood pressure.
  2. Respiratory dysfunction: Kussmaul breathing in ketoacidosis, shortness of breath.
  3. Swallowing and chewing disorders.
  4. Movement disorders.
  5. Loss of taste.
  6. Impaired reflexes.
  7. Speech disorder.

If this part of the brain is damaged, the function of the respiratory center may be turned off, leading to asphyxia (suffocation). Pressor dysfunction causes a drop in blood pressure.

Includes swallowing problems and choking on food. A person's heart rate slows down and shortness of breath occurs. Since the activity of the hypoglossal nerve is disrupted, the patient loses the ability to pronounce words and chew. Saliva may leak from the mouth.

As can be seen from the article, the medulla oblongata is important in ensuring human life. Blood circulation and breathing are its most important functions. Damage to this section can lead to death.