The brain is the most important organ that regulates absolutely all aspects of human life. It has a rather complex anatomical structure. One of its significant sections is the medulla oblongata, the structure and functions of which will be discussed in detail in our article.

Classmates

They are divided into several groups:

1. Protective - hiccups, sneezing, coughing, vomiting, etc.
2. Cardiac and vascular reflexes.
3. Regulating the vestibular apparatus.
4. Digestive.
5. Reflexes of pulmonary ventilation.
6. Setting reflexes responsible for maintaining posture and muscle tone.

Anatomy

This part of the central nervous system directly involved in information processing, which comes to it from all receptors human body.

This section of the nervous system contains the nuclei of five pairs of cranial nerves. They are grouped in the caudal part below the bottom of the 4th ventricle:

Pathways

Pass through the medulla oblongata several conducting sensory pathways from the spinal region to the overlying parts of the central nervous system:

1. Thin.
2. Wedge-shaped.
3. Spinothalamic.
4. Spinocerebellar.

Localization of these pathways in the medulla oblongata and spinal cord identical.

In the lateral part of the white matter are located efferent pathways:

1. Rubrospinal.
2. Olivospinal.
3. Tectospinal.
4. Reticulospinal.
5. Vestibulospinal.

The fibers of the corticospinal motor tract pass through the ventral part. Its fibers in the medulla oblongata are formed into special formations, which are called pyramids. At the level of the pyramids, 80% of the fibers of the descending tracts form a cross between themselves. The remaining 20% ​​of the fibers form a cross and pass to the opposite side below - at the level of the spinal cord.

Basic functions

Exists large number problems that the medulla oblongata is called upon to solve. Functions of this part of the nervous system are divided into the following groups:

1. Sensory.
2. Reflex.
3. Integrative.
4. Conductor.

Below they will be discussed in more detail.

Sensory

This type of function is in the acceptance by neurons of signals from sensory receptors in response to environmental influences or changes in internal environment body. These receptors are formed from sensory epithelial cells or from the nerve endings of sensory neurons. The cell bodies of sensory neurons are located in the peripheral ganglia or in the brain stem itself.

The neurons of the brain stem analyze the signals sent by the respiratory system. This may be a change in the gas composition of the blood or stretching of the pulmonary alveoli. These indicators are used to analyze not only hemodynamics, but also the state of metabolic processes. In addition, the activity of the respiratory system is analyzed in the nuclei. Based on the results of such an assessment, reflex regulation of the functions of respiration, blood circulation, digestive system.

In addition to internal signals, the centers of the medulla oblongata regulate and process signals about changes in the external environment- from temperature receptors, taste, auditory, tactile or pain.

From the centers, signals travel through conductive fibers to higher parts of the brain. There, a more refined analysis and identification of these signals is carried out. As a result of processing this data, certain emotional-volitional and behavioral reactions are formed in the cerebral cortex. Some of them are carried out in the same way using the structures of the medulla oblongata. In particular, a decrease in oxygen levels in the blood and an accumulation of carbon dioxide can lead to the development of unpleasant sensations and a negative emotional state in a person. As behavioral therapy, the person begins to seek access to fresh air.

Conductor

Conductive functions consist in the fact that nerve impulses are conducted from sensory components through this area to other parts of the nervous system.

Nerve impulses of afferent nature arrive at the centers from sensory receptors located:

All these impulses are conducted along the fibers of the cranial nerves to the corresponding nuclei, where they are analyzed and an appropriate reflex reaction is formed in response to stimuli. From the centers of this department, efferent nerve impulses can be sent to other parts of the trunk or cortex in order to carry out more complex behavioral reactions in response to stimuli.

Integrative

This type of function can manifest itself in the formation of complex reactions, which cannot be limited to the simplest reflex actions. Neurons carry information about certain regulatory processes, the implementation of which requires joint participation with other parts of the nervous system, including the cerebral cortex. The algorithm for such complex actions is programmed in the neurons of this part of the brain.

An example of such an effect would be a compensatory change in position eyeballs when changing the position of the head - nodding, rocking, etc. In this case, there is a coordinated interaction of the nuclei of the oculomotor nerves and the vestibular apparatus with the participation of the components of the medial longitudinal fasciculus.

Some of the neurons of the mesh structure have autonomy and automatic functions. Its task is to coordinate nerve centers in various parts of the central nervous system and to tonize them.

Reflex

The most important reflex functions are This is the regulation of skeletal muscle tone and maintaining posture in space. In addition, reflex functions include the body’s protective actions, as well as organizing and maintaining balance. respiratory system and blood circulation.

The medulla oblongata (myelencephalon) lies at the base of the GM, being a continuation of the SC. Therefore, many features of its structure are similar to SM. The shape of the medulla oblongata resembles a truncated cone. Its length is approximately 30 mm, width at the base - 10 mm, at the top - 24 mm. Its lower border is the exit point of the first pair of spinal nerves. Above the medulla oblongata there is the pons, which on the ventral side looks like a constriction through the brain stem. The medulla oblongata is divided into two symmetrical halves by the anterior median fissure, which passes from the SC, and the posterior median sulcus, which continues a similar groove of the SC.

The medulla oblongata, together with the pons and cerebellum, makes up the hindbrain, the cavity of which is the fourth cerebral ventricle. The bottom of the IV ventricle, formed by the dorsal surface of the medulla oblongata and the pons, is called the rhomboid fossa.

On the ventral surface of the medulla oblongata, on the sides of the median fissure, there are two longitudinal cords of white matter - pyramids (Fig. 6.5). These are fibers of the corticospinal tract coming from the cortex cerebral hemispheres in SM (see paragraph 5.4). At the border with the SM, most of the fibers of this tract intersect, forming a pyramidal decussation. This area is the ventral border between the GM and SM.

Lateral to the pyramids lie oval elevations - olives, separated from them by the anterior lateral groove. In the depths of the olives there is gray matter - the inferior olivary complex (nuclei of the inferior olives). The complex consists of the nucleus of the inferior olive (p. olivaris inferior) and two additional nuclei of the inferior olive - medial and dorsal. This is where the spino-olivary tract coming from the SC ends. The inferior olive also receives many other afferents, primarily from the cerebral cortex and the red nucleus of the midbrain. These fibers form a dense capsule surrounding the nucleus. The olives themselves send their efferents to the cerebellar cortex (olivo-cerebellar tract). The olives, together with the cerebellum, are involved in maintaining posture and motor learning.

The VI, VII and VIII pairs of cranial nerves (abducens, facial and glossopharyngeal) emerge from the transverse fissure separating the medulla oblongata from the pons, and the hypoglossal nerve (XII pair) emerges from the anterior lateral sulcus. The glossopharyngeal, vagus and accessory nerves (IX, X and XI pairs) sequentially emerge from the outer edge of the olive.

Rice. 6.5

Roman numerals indicate the corresponding cranial nerves: V - trigeminal;

VI - abducent; VII - facial; VIII - vestibulo-auditory; IX - glossopharyngeal;

X - wandering; XI - additional; XII - sublingual

On the dorsal surface of the medulla oblongata, on the sides of the posterior median sulcus, there are two fascicles - gentle (more medial) and wedge-shaped (more lateral) (Fig. 6.6). This is a continuation of the paths of the same name ascending from the SM (see paragraph 5.4). But on the sides of the rhomboid fossa, thickenings are visible on the bundles - tubercles of the tender and wedge-shaped nuclei. Below them lie these nuclei, on which the fibers of the corresponding bundles end. The medial lemniscus begins from the tender and cuneate nuclei (see below). Some of the fibers from here go to the cerebellum.

Let us list the kernels included in gray matter of the medulla oblongata.

• 1. Nuclei of the trigeminal, facial, vestibulo-auditory, glossopharyngeal, vagus, accessory and hypoglossal nerves (see paragraph 6.2).
• 2. Gentle and wedge-shaped nuclei.
• 3. Olive kernels.
• 4. RF cores (see paragraph 6.7).

White matter occupies a large volume. It includes the so-called transit paths, i.e. ascending and descending tracts passing through the medulla oblongata without interruption (without forming synapses on its neurons). These include all spinal tracts, with the exception of the gentle and sphenoid fasciculi, as well as the spino-olivary tract, which end directly in the medulla oblongata. Transit tracts occupy the ventral and lateral parts of the medulla oblongata.

In addition, several new tracts begin here.

Rice. 6.6.

• 1. Inferior cerebellar peduncles ( pedunculus cerebellaris inferior)- these are pathways connecting the cerebellum with other brain structures (the cerebellum has three pairs of legs in total). The inferior peduncles include the olivocerebellar tract, the posterior spinocerebellar tract, fibers from the vestibular nuclei of the brainstem, and fibers from the gracile and cuneate nuclei.
• 2. Ascending tract - medial loop, or medial lemniscus (lemniscus medialis). Its fibers are formed by the axons of the cells of the tender and cuneate nuclei, which first pass to the other side and then go to the thalamus. The medial lemniscus is joined by spinothalamic tracts, as well as fibers from the sensory nuclei of the brain stem (nucleus of the solitary tract and nuclei of the trigeminal nerve), also ending in the thalamus. As a result, this entire system carries out various types of somatic (pain, skin, muscle, visceral) and also taste sensitivity into the diencephalon, and then into the cerebral cortex.
• 3. Medial longitudinal fasciculus (fasciculus longitudinalis medialis) starts from the lateral vestibular nucleus (Deiters nucleus). Some of the fibers of this pathway begin in some nuclei of the midbrain, so we will talk about it in more detail below (see paragraph 6.6).

Thus, functions of the medulla oblongata - reflex and conductive.

Conductor function lies in the fact that ascending and descending pathways pass through the brain stem (including the medulla oblongata), connecting the overlying parts of the brain, up to the cerebral cortex, with the SC. Collaterals from these pathways can end on the nuclei of the medulla oblongata and pons.

Reflex function connected with the nuclei of the brain stem, through which reflex arcs close.

It should be noted that in the medulla oblongata (mainly in the reticular nuclei) there are many vital centers - respiratory, vasomotor, centers of food reflexes (salivary, swallowing, chewing, sucking), centers of protective reflexes (sneezing, coughing, vomiting), etc. Therefore, damage to the medulla oblongata (stroke, trauma, edema, hemorrhage, tumors) usually leads to very serious consequences.

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. Is the oldest education 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 (CSF), 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. Has formations (pyramids) that control motor function and passing 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 regulating blood pressure, 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 (increasing 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 increases its activity gastrointestinal tract. Stimulates the release of hydrochloric acid, pancreatic enzymes, accelerates peristalsis of the large intestine. Its sensory 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. Action medicines neuroleptics.

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. Because activity is disrupted hypoglossal nerve, 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.

Historically, the formation of the central nervous system has led to the fact that the human medulla oblongata is a kind of center of vital functions, for example, control of breathing and the functioning of the cardiovascular system.

Location of the medulla oblongata

Like the rest of the brain, the medulla oblongata is located in the cranial cavity. He takes small space in its occipital part, at the top bordering the pons, and downwards through the foramen magnum without a clear boundary passing into the spinal cord. Its anterior median fissure is a continuation of the spinal cord groove of the same name. In an adult, the length of the medulla oblongata is 8 cm, its diameter is about 1.5 cm. In the initial sections, the medulla oblongata has an elongated shape, reminiscent of thickenings of the spinal cord. Then it seems to expand, and before it passes into the diencephalon, massive thickenings extend from it in both directions. They are called the peduncles of the medulla oblongata. With their help, the medulla oblongata is connected to the hemispheres of the cerebellum, which, as it were, “sits” on its last third.

Internal structure of the medulla oblongata

Both externally and internally, this part of the brain has a number of features characteristic only of it. On the outside, it is covered with a smooth epithelial membrane, which consists of satellite cells, and inside there are numerous wire pathways. Only in the region of the last third there are clusters of neuron nuclei. These are the centers of breathing, control of vascular tone, heart function, as well as some simple innate reflexes.

Purpose of the medulla oblongata

The structure and functions of the medulla oblongata determine its special place in the entire nervous system. He's playing important role as a connecting link between all other structures of the brain and the spinal cord. So, it is through it that the cerebral cortex receives all the information about the contacts of the body with surfaces

In other words, thanks to the medulla oblongata, almost all tactile receptors work. Its main functions include:

1. Participation in work regulation critical systems and organs. The medulla oblongata contains the respiratory center, the vascular-motor center and the center for regulating heart rate.
2. Carrying out some reflex activity with the help of neurons: blinking of the eyelids, coughing and sneezing, gag reflexes, as well as regulation of lacrimation. They belong to the so-called protective reflexes, which ensure the human body’s ability to resist harmful environmental factors.
3. Providing trophic reflexes. It is thanks to the medulla oblongata that children in the first years of life have a persistent sucking reflex. This also includes the vital reflexes of swallowing and the secretion of digestive juices.
4. Finally, it is this part of the brain that is considered the most important link in the formation of a person’s stability and coordination in space.

Brain in all people it is considered the most important organ of the central nervous system (CNS). It is completely formed from cells, nerve endings and their processes. It is also divided into several sections, which include the cerebellum, midbrain, forebrain, pons, medulla oblongata and others.

And although medicine has made great strides forward, scientists and doctors continue to study this organ, since the secrets of its structure and functions have not yet been fully revealed.

Interesting fact: people of different sexes have different brain masses. In men it weighs 1345-1400 grams, and in women 1235-1275 grams. At the same time, scientists have proven that mental abilities do not depend on the mass of the brain. On average, the human brain is mature age is 2% of total mass human body.

Medulla oblongata

Division of the medulla oblongata(lat. Myelencephalon, Medulla oblongata) is one of the most important links that make up the structure of the brain. This section is represented by a continuation of the spinal cord in the form of its thickening, and also connects the brain to the spinal cord.

Oblong section looks very much like an onion. Below the medulla oblongata is the spinal cord, and above it is the pons. It turns out that this section connects the cerebellar part and the brain bridge with the help of special processes (legs).

U children in the first month of their life, this section is larger in size compared to other sections. Around the age of seven and a half, nerve fibers begin to become covered with a myelin sheath. This gives them additional protection.

Structure and structure of the oblongata section

In adults, the length of the oblongata is approximately 2.5-3.1 centimeters, which is where it got its name.

Its structure is very similar to the spinal cord and consists of gray and white brain matter:

1. Gray part located in the center of the brain and forms nuclei (clumps).
2. White part is located above and envelops the gray matter. It consists of fibers (long and short).

Nuclei oblongata part of the brain They are different, but they perform one function and connect it with other departments.

Types of kernels:

• olive-like kernels;
• Burdach and Gaulle kernels;
• nuclei of nerve endings and cells.

These kernels include:

• sublingual;
• accessory vagus;
• glossopharyngeal and descending nuclei of the ternary nerves.

Paths (descending and ascending) connect the main brain with the spinal cord, as well as with some parts. For example, with the reticular pharmacy, striopalidal system, cerebral cortex, limbic system and upper parts of the brain.

The medulla oblongata acts as a conductor for some reflex functions of the body.

These include:

• vascular;
• cardiac;
• digestive;
• vestibular;
• skeletal;
• protective.

It also contains some regulatory centers.

These include:

• management of respiratory functions;
• regulation of saliva secretion;
• regulation of vasomotor functions.

Ask your doctor about your situation

Functions of the oblongata

This part of the brain performs very important tasks, which are necessary for proper operation all systems and functions of the body.

However, doctors consider the most important functions to be reflexive and conductive:

1. Reflex function. It is responsible for the body’s protective reactions that prevent the entry of germs and other pathogens and microorganisms. Reflex functions include lacrimation, coughing, sneezing and others. These functions also help the body remove harmful substances from the body.
2. Conductor function. It is activated and acts through ascending and descending pathways that transmit signals to systems and organs about a threat. With its help, the body can prepare for “defense.” Two-way communication Thanks to the pathways, the cortex, diencephalon, midbrain, cerebellum and spinal cord are connected.

Doctors also highlight the associative or sensory function:

• It provides facial sensitivity.
• Responsible for taste buds and vestibular stimuli.

In action this function lead impulses, which come from external stimuli to the medulla oblongata of the brain. There they are processed and move to the subcortical zone. After processing the signal, chewing, swallowing or sucking reflexes occur.

If damage to the medulla oblongata occurs, this will provoke improper functioning of the muscles of the face, neck and head, and possibly paralysis of the entire body.

Surfaces of the oblong section

The medulla oblongata has several surfaces.

These include:

• ventral (front) surface;
• dorsal (posterior) surface;
• two side surfaces.

All surfaces connected between themselves, and between their pyramids there is a median gap medium depth. It is part of the median fissure, which is located in the spinal cord.

Ventral surface

Ventral surface consists of two lateral convex pyramid-shaped parts, which are narrowed downwards. They are formed by pyramidal tracts. In the median fissure, the fibers of the pyramidal parts intersect with the approach to the adjacent part and enter the cable fibers of the spinal cord.

The places where crossover occurs are edge medulla oblongata at the junction with the spinal cord. Olives are located near the pyramids. These are small elevations that are separated from the pyramidal surface by an anterolateral groove. The roots of the sublingual nerve endings and the nerves themselves extend from this groove.

Dorsal surface

Dorsal surface doctors call back surface medulla oblongata of the brain. On the sides of the groove are the posterior cords, which are bounded on both sides by the posterolateral grooves. Each of the cords is divided by the posterior intermediate groove into two bundles: thin and wedge-shaped.

The main task of the beam is impulse transmission from the lower body. The bundles in the upper part of the oblong section expand and transform into thin tubercles, in which the nuclei of the bundles are located.

The main task wedge-shaped bundles is considered to be the conduction and transmission of impulses from the joints, bones and muscles of the upper and lower limbs. The expansion of each bundle allows the formation of additional wedge-shaped tubercles.

Posterolateral groove serves as a kind of outlet for the roots of the glossopharyngeal, accessory and vagus nerves.

Between the dorsal and ventral surfaces are located side surfaces. They also have lateral grooves that originate in the spinal cord and enter the medulla oblongata.

The medulla oblongata of the brain of the head organizes the smooth and coordinated functioning of the entire brain. The centers of nerve cells and endings, as well as pathways, allow information to quickly reach the required part of the brain and send a signal at the neuron level.

Cores, which are located on the surfaces of the medulla oblongata, allow incoming impulses to be converted into information that can be transmitted further.