The hypothalamus is one of the main structures involved in the formation of behavioral reactions of the body, which are necessary for the constancy of the internal environment. Stimulation of its nuclei leads to the formation of purposeful behavior - eating, sexual, aggressive, etc. It also plays a major role in the emergence of the body’s basic drives (motivations).

In vertebrates, the hypothalamus is the main subcortical center for the integration of visceral processes. It controls all the basic homeostatic functions of the body. The integrative function of the hypothalamus is ensured by autonomic, somatic and endocrine mechanisms.

Transmission of information in the hypothalamus

Sensitive information from internal organs and the surface of the body enters the hypothalamus along the ascending spinobulbar tract. Some of them pass through the thalamus, others through the limbic region of the midbrain, and others follow as yet incompletely identified polysynaptic pathways. In addition, the hypothalamus is equipped with its own specific “inputs”. It contains osmoreceptors that are highly sensitive to changes in the osmotic pressure of the internal environment and thermoreceptors that are sensitive to changes in blood temperature. The efferent pathways of the hypothalamus are polysynaptic. They associate it with the reticular formation of the brain stem and the nuclei of the spinal cord. Descending influences of the hypothalamus provide regulation of functions mainly through the autonomic nervous system. At the same time, an important component in the implementation of descending influences of the hypothalamus are pituitary hormones . In addition to afferent and efferent connections, there is a commissural pathway in the hypothalamus. Thanks to it, the medial hypothalamic nuclei of one side come into contact with the medial and lateral nuclei of the other side.

Hypothalamic connections

Numerous connections of the hypothalamus with other brain formations contribute to the generalization of excitations arising in the cells of the hypothalamus. Excitation primarily spreads to the limbic structures of the brain and through the nuclei of the thalamus to the anterior parts of the cerebral cortex. The degree of distribution of ascending activating influences of the hypothalamus depends on the magnitude of the initial excitation of the hypothalamic centers.

Hypothalamus and behavioral reactions of the body

Hypothalamus- one of the main structures involved in the formation of behavioral reactions of the body, which are necessary for the constancy of the internal environment. Stimulation of its nuclei leads to the formation of purposeful behavior - eating, sexual, aggressive, etc. It also plays the main role in the emergence of the basic drives (motivations) of the body.

Blood supply to the hypothalamus

The main source of arterial blood supply to the hypothalamic nuclei is the arterial circle of the brain. Its branches provide an abundant isolated blood supply to individual groups of nuclei, the capillary network of which is several times denser than the blood supply to other parts of the nervous system. The capillary network of the hypothalamus is distinguished by high permeability for large molecular compounds. The virtual absence of a blood-brain barrier in this area allows these blood compounds to have a direct effect on hypothalamic neurons.

Hypothalamic-pituitary system

Numerous neural and vascular connections between the hypothalamus and pituitary gland form the basis of a functional complex called the hypothalamic-pituitary system. The main purpose of the complex is to integrate the nervous and hormonal regulation of the visceral functions of the body. From the hypothalamus, it is carried out in two ways: paraadenopituitary (bypassing the adenohypophysis) and transadenopituitary (through the adenohypophysis).

Pituitary hormones

The release of hormones from the anterior pituitary gland is influenced by the hormones of neurons in the hypophysiotropic zone of the medial region of the hypothalamus. They are able to have a stimulating and inhibitory effect on pituitary cells. In the first case, these are the so-called releasing factors (liberins), in the second - inhibitory factors (statins). Regulation of visceral functions by the hypothalamic-pituitary system is carried out according to the feedback principle. Its effect is manifested even after complete separation of the medial region of the hypothalamus from other parts of the brain. The role of the central nervous system is to adapt this regulation to the internal and external needs of the body.

Hypothalamic cells

The cells of the hypothalamus are selectively sensitive to the content of certain substances in the blood and with any change in their concentration they become excited. For example, hypothalamic neurons are sensitive to the slightest deviations in blood pH, O2 and CO2 voltage, and ion content, especially K and Na. Thus, the supraoptic nucleus contains cells that are selectively sensitive to changes in blood osmotic pressure, the ventromedial nucleus – to glucose content, and the anterior hypothalamus – to sex hormones. Consequently, the cells of the hypothalamus function as receptors that perceive changes in homeostasis. They have the ability to transform humoral changes in the internal environment into a nervous process - biologically colored excitation. However, they can be selectively activated not only by changes in certain blood constants, but also by nerve impulses from the corresponding organs associated with this need. Receptor cells operate according to a trigger type. Excitation does not arise in them immediately as soon as any blood constant changes, but after a certain period of time, when their depolarization reaches a critical level. Consequently, the neurons of the motivational centers of the hypothalamus are distinguished by the periodicity of their work. In the case when the change in the blood constant is maintained for a long time, the depolarization of neurons rises to a critical level and the state of excitation is established at this level as long as there is a change in the constant that caused the development of the excitation process. The constant impulse activity of these neurons disappears only when the irritation that caused it is eliminated, i.e., the content of one or another blood factor is normalized. Excitation of some cells of the hypothalamus can occur periodically after a few hours, as, for example, with a lack of glucose, others - after several days or even months, as, for example, with a change in the content of sex hormones.

Removal of the hypothalamus

Destruction of the nuclei or removal of the entire hypothalamus is accompanied by a disruption of the homeostatic functions of the body. The hypothalamus plays a leading role in maintaining optimal levels of metabolism (protein, carbohydrate, fat, mineral, water) and energy, in regulating the temperature balance of the body, and the activity of the cardiovascular, digestive, excretory, and respiratory systems. The functions of the endocrine glands are influenced by it. When hypothalamic structures are excited, the nervous component of complex reactions is necessarily supplemented by the hormonal component.

Posterior nuclei of the hypothalamus

Studies have shown that stimulation of the posterior nuclei of the hypothalamus is accompanied by effects similar to irritation of the sympathetic nervous system: dilation of the pupils and palpebral fissure, increased heart rate, increased blood pressure, inhibition of motor activity of the stomach and intestines, increased concentration of adrenaline in the blood. The 3rd region of the hypothalamus has an inhibitory effect. influence on sexual development. Its damage also leads to hyperglycemia, and in some cases to the development of obesity. Destruction of the posterior nuclei of the hypothalamus is accompanied by a complete loss of thermoregulation. The body temperature of these animals cannot be maintained. Reactions that occur upon stimulation of the posterior hypothalamus and are accompanied by activation of the sympathetic nervous system, mobilization of the body's energy, and an increase in the ability to exercise are called ergotropic.

Anterior nuclei of the hypothalamus

Stimulation of the group of anterior nuclei of the hypothalamus is characterized by reactions similar to irritation of the parasympathetic nervous system, constriction of the pupils and palpebral fissure, a decrease in heart rate, a decrease in blood pressure, increased motor activity of the stomach and intestines, activation of the secretion of gastric glands, increased insulin secretion and, as a result, decrease in blood glucose levels. The group of anterior nuclei of the hypothalamus has a stimulating effect on sexual development. The mechanism of heat loss is also associated with it. The destruction of this area leads to disruption of the heat transfer process, as a result of which the body quickly overheats.

Middle nuclei of the hypothalamus

The middle group of hypothalamic nuclei provides mainly regulation of metabolism. The study of the regulation of eating behavior has shown that it occurs as a result of reciprocal interactions of the lateral and ventromedial hypothalamic nuclei. Activation of the first causes increased food consumption, and its bilateral destruction is accompanied by a complete refusal of food, up to exhaustion and death of the animal. On the contrary, increased activity of the ventromedial nucleus reduces the level of food motivation. When this nucleus is destroyed, an increase in food consumption (hyperphagia) and obesity occur. These data made it possible to regard the ventromedial nuclei as structures through which food intake is limited, i.e., associated with satiety, and the lateral nuclei as structures that increase the level of food motivation, i.e., associated with hunger. At the same time, it has not yet been possible to identify the functional or structural accumulations of neurons responsible for this or that behavior. Consequently, cellular formations that ensure the formation of holistic behavior from individual reactions should not be considered as anatomically limited structures known as the hunger center and the satiety center. Probably, groups of hypothalamic cells associated with the performance of any function differ from each other in the nature of afferent and efferent connections, synaptic organization and mediators. It is assumed that the neural networks of the hypothalamus contain numerous programs and their activation through signals from other parts of the brain or interoceptors leads to the formation of the necessary behavioral and neurohumoral reactions. Studies of the role of the hypothalamus by irritating or destroying its nuclei have led to the conclusion that the areas responsible for food and water intake appear to overlap each other. The most increased need for water was observed with stimulation of the paraventricular nucleus of the hypothalamus.

Interaction of the hypothalamus with other parts of the brain

The hypothalamus is in continuous cyclical interactions with other parts of the subcortex and cerebral cortex. Due to the fact that nervous and humoral signaling about various internal needs is addressed to the hypothalamic nuclei, they acquire the significance of a trigger mechanism for motivational excitations. The introduction of neurotropic substances of specific action can selectively block various hypothalamic mechanisms involved in the formation of such body states as fear, hunger, thirst, etc. The hypothalamus is under the regulatory influence of the cerebral cortex. Receiving information about the initial state of the body and the environment, cortical neurons exert a descending influence on all subcortical structures, including the hypothalamus, regulating their level of excitation. Cortical mechanisms suppress many emotions and primary excitations formed with the participation of the hypothalamic nuclei. Therefore, removal of the cortex often leads to the development of reactions of imaginary rage, expressed in dilated pupils, tachycardia, salivation, increased intracranial pressure, etc. Thus, the hypothalamus, having a well-developed and complex system of connections, occupies a leading place in the regulation of many functions of the body and, above all, in the constancy of the internal environment. The function of the autonomic nervous system and endocrine glands is under its control. It is involved in the regulation of eating and sexual behavior, sleep and wakefulness, emotional activity, maintaining body temperature, etc.

Responsible for the mechanisms of wakefulness and sleep, changes in body temperature and metabolic processes in the body. The performance of all organs and tissues of the body depends on it. Human emotional reactions are also under the control of the hypothalamus. In addition, the hypothalamus controls the work of the endocrine glands, participates in the digestion process, as well as in procreation. The hypothalamus is located in the brain under the visual thalamus - the thalamus. Therefore, hypothalamus, translated from Latin means “ hypothalamus».

• The hypothalamus is the size of the phalanx of the thumb.
• Scientists have found centers of “heaven” and “hell” in the hypothalamus. These areas of the brain are responsible for pleasant and unpleasant sensations in the body.
• The division of people into “larks” and “night owls” is also within the competence of the hypothalamus.
• Scientists call the hypothalamus the “inner sun of the body” and believe that further study of its capabilities can lead to an increase in human life expectancy, to victory over many endocrine diseases, as well as to further exploration of space, thanks to a controlled lethargic sleep into which astronauts can be immersed, covering distances of tens and hundreds of light years.

Healthy foods for the hypothalamus

• Raisins, dried apricots, honey - contain glucose necessary for the full functioning of the hypothalamus.
• Greens and leafy vegetables. Lovely and potassium.
• They are excellent antioxidants. Protect the hypothalamus from the risk of hemorrhage and stroke.
• Milk and dairy products. They contain B vitamins, which are necessary for the proper functioning of the nervous system, as well as calcium and other nutrients.
• Eggs . They reduce the risk of stroke due to the content of substances that are beneficial for the brain.
• Coffee, dark chocolate. In small quantities they tone up the hypothalamus.
• Bananas, tomatoes, oranges.
• They lift your spirits. They facilitate the work of not only the hypothalamus, but also all structures of the brain. Useful for the nervous system, the activity of which is closely related to the work of the hypothalamus.
• Walnuts . Stimulates the performance of the hypothalamus. Slow down the aging process of the brain. Rich in healthy fats, vitamins and microelements.
• Carrot . Slows down the aging process in the body, stimulates the formation of young cells, and participates in the conduction of nerve impulses.

Sea kale. Contains substances necessary to provide the hypothalamus with oxygen. The large amount of iodine contained in seaweed helps fight insomnia and irritability, fatigue and stress.

• Fatty fish and vegetable oils. They contain polyunsaturated fatty acids, which are important components of the nutrition of the hypothalamus.
• They prevent cholesterol deposition and stimulate hormone production.
• For the full functioning of the hypothalamus, you need:
• Eliminate alcoholic beverages and get rid of harmful cravings for smoking, which harm the functioning of the nervous system, with the activity of which the hypothalamus is closely connected.
• Avoid watching TV and working on the computer before bed.
• Otherwise, due to a violation of the light regime of the day, disruptions in the functioning of the hypothalamus and the entire nervous system may occur.

In order to prevent overexcitation of the hypothalamus, it is recommended to wear sunglasses on a bright sunny day.

Traditional methods of restoring the functions of the hypothalamus

1. The causes of dysfunction of the hypothalamus are:
2. 1 Infectious diseases, intoxication of the body.
3. 2 Disturbances in the functioning of the nervous system.

3 Weak immunity. In the first case

Anti-inflammatory herbs (chamomile, calendula, St. John's wort) can be used - on the recommendation of a doctor. For intoxication, iodine-containing products are useful - chokeberry, seaweed, feijoa, walnuts. In the second case

When the functioning of the nervous system is disrupted, tonics (chicory, coffee) are used, or vice versa, sedatives - tincture of valerian, motherwort and hawthorn, pine baths.

For tachycardia and an unreasonable increase in pressure associated with improper functioning of the hypothalamus, water procedures are useful: a warm shower followed by vigorous rubbing of the skin.

For depressive conditions, a decoction of St. John's wort herb helps well, of course, if there are no medical contraindications for use!

It is believed that eye strain causes disturbances in the functioning of the hypothalamus. Warm eye baths will help relieve excess stress and restore brain function. Third case

– weak immunity, can be successfully treated with tinctures of ginseng, zamanikha, and Schisandra chinensis. The use of royal jelly gives good results for strengthening the immune system.

• Harmful foods for the hypothalamus Alcohol
• . Causes vasospasm, destruction of hypothalamic cells and disturbances in the functioning of the nervous system. Salt
• . Excess salt causes overexcitation of the nerves that go to the hypothalamus. In addition, very salty foods cause an increase in blood pressure, which in some cases can lead to hemorrhages in the brain structures. Fat meat

Hypothalamus . Contains harmful fats that can cause cholesterol plaques in the blood vessels of the brain, disrupting the nutrition of the hypothalamus. I

department of the diencephalon, which plays a leading role in the regulation of many functions of the body, and above all the constancy of the internal environment, G. is the highest vegetative center that carries out the complex integration of the functions of various internal systems and their adaptation to the integral activity of the body, plays a significant role in maintaining the optimal level metabolism and energy, in thermoregulation, in the regulation of the digestive, cardiovascular, excretory, respiratory and endocrine systems. Under the control of G. are such as the Pituitary gland , Thyroid , gonads (see testicle , Ovaries) , Pancreas , Adrenal glands and etc.

The hypothalamus has three vaguely demarcated regions: anterior, middle and posterior. In the anterior region of the brain, neurosecretory cells are concentrated, where they form the supraopticus (nucl. supraopticus) and paraventricular (nucl. paraventricularis) nuclei on each side. The optic nerve consists of cells lying between the wall of the third ventricle of the brain and the dorsal surface of the optic chiasm. The paraventricular nucleus has plates between the fornix (fornix) and the wall of the third ventricle of the brain. The axons of the neurons of the paraventricular and supravisual nuclei, forming the hypothalamic-pituitary, reach the posterior lobe of the pituitary gland, where they accumulate, from where they enter the.

In the middle region of the brain, around the lower edge of the third ventricle of the brain, lie the gray tuberous nuclei (nucll. tuberaies), arcuately covering the infundibulum of the pituitary gland. Above and slightly lateral to them are the large ventromedial and dorsomedial nuclei.

In the posterior region of the brain there are nuclei consisting of scattered large cells, among which there are clusters of small cells. This section also includes the medial and lateral nuclei of the mastoid body (nucll. corporis mamillaris mediales et laterales), which on the lower surface of the diencephalon look like pairs hemispheres. The cells of these nuclei give rise to one of the so-called G. projection systems into the oblongata and. The largest cell cluster is the medial nucleus of the mastoid body. Anterior to the mammillary bodies protrudes the bottom of the third ventricle of the brain in the form of a gray mound (tuber cinereum), formed by a thin plate of gray matter. This protrusion extends into a funnel, which passes distally into the pituitary stalk and further into the posterior lobe of the pituitary gland. The expanded upper part of the funnel - the median eminence - is lined with ependyma, followed by a layer of nerve fibers of the hypothalamic-pituitary fascicle and thinner fibers originating from the nuclei of the gray tuberosity. The outer part of the median eminence is formed by supporting neuroglial (ependymal) fibers, between which numerous nerve fibers lie. Deposition of neurosecretory substances is observed in and around these nerve fibers. Thus, the hypothalamus is formed by a complex of nerve conduction and neurosecretory cells. In this regard, the regulatory influences of G. are transmitted to effectors, incl. and to the endocrine glands, not only with the help of hypothalamic neurohormones carried by the bloodstream and, therefore, acting humorally, but also along efferent nerve fibers.

G.’s role in the regulation and coordination of the functions of the autonomic nervous system is significant. The nuclei of the posterior region of the nervous system participate in the regulation of the function of its sympathetic part, and the functions of the parasympathetic part of the autonomic nervous system are regulated by the nuclei of its anterior and middle regions. the anterior and middle regions of the bladder cause reactions characteristic of the parasympathetic nervous system - a decrease in heartbeat, increased intestinal motility, increased tone of the bladder, etc., and the posterior region of the bladder is manifested by an increase in sympathetic reactions - increased heart rate, etc.

Vasomotor reactions of hypothalamic origin are closely related to the state of the autonomic nervous system. Various types of arterial hypertension that develop after G. stimulation are caused by the combined influence of the sympathetic part of the autonomic nervous system and the release of adrenaline by the adrenal glands (Adrenal glands). , although in this case the influence of the neurohypophysis cannot be excluded, especially in the genesis of stable arterial hypertension.

From a physiological point of view, G. has a number of features, primarily this concerns its participation in the formation of behavioral reactions that are important for maintaining the constancy of the internal environment of the body (see Homeostasis) . G.'s irritation leads to the formation of purposeful behavior - eating, drinking, sexual, aggressive, etc. The hypothalamus plays a major role in the formation of the body’s basic drives (see Motivations) . In some cases, when the superomedial nucleus and gray-tuberous region of G. are damaged, excessive polyphagia (bulimia) or cachexia is observed as a result. posterior sections of G. causes hyperglycemia. The role of the supravisual and paraventricular nuclei in the mechanism of diabetes insipidus has been established (see Diabetes insipidus) . Activation of neurons in the lateral G. causes the formation of food. With bilateral destruction of this section, the food supply is completely eliminated.

Extensive connections of the brain with other structures of the brain contribute to the generalization of excitations that arise in its cells. G. is in continuous interaction with other parts of the subcortex and cerebral cortex. This is precisely what underlies G.’s participation in emotional activity (see Emotions) . The cerebral cortex can have an inhibitory effect on the functions of the brain. Acquired cortical mechanisms suppress many of the primary impulses that are formed with its participation. Therefore, it often leads to the development of a reaction of “imaginary rage” (dilation of the pupils, development of intracranial hypertension, increased salivation, etc.).

The hypothalamus is one of the main structures involved in the regulation of sleep cycles (Sleep) and wakefulness. Clinical studies have established that lethargic sleep in epidemic encephalitis is caused precisely by damage to the brain. The posterior region of the brain plays a decisive role in maintaining a state of wakefulness. Extensive destruction of the middle region of the brain in the experiment led to the development of prolonged sleep. Sleep disturbance in the form of narcolepsy is explained by damage to G. and the rostral part of the reticular formation of the midbrain.

G. plays an important role in thermoregulation (Thermoregulation) . Destruction of the posterior sections of the liver leads to a persistent decrease in body temperature.

G. cells have the ability to transform humoral changes in the internal environment of the body into a nervous process. G.'s centers are characterized by pronounced selectivity of excitation depending on various changes in blood composition and acid-base state, as well as nerve impulses from the corresponding organs. in G.'s neurons, which have selective reception in relation to blood constants, does not occur immediately as soon as any of them changes, but after a certain period of time. If the change in the blood constant is maintained for a long time, then in this case the G. neurons quickly rise to a critical value and the state of this excitation is maintained at a high level as long as there is a change in the constant. Excitation of some G. cells can occur periodically after a few hours, as, for example, during hypoglycemia, others - after several days or even months, as, for example, when the content of sex hormones in the blood changes.

Informative methods for studying G. are plethysmographic, biochemical, X-ray studies, etc. Plethysmographic studies (see Plethysmography) reveal a wide range of changes in G. - from a state of autonomic vascular instability and paradoxical reaction to complete areflexia. In biochemical studies in patients with G.'s lesions, regardless of its cause (inflammatory process, etc.), an increase in the content of catecholamines and histamine in the blood is often determined, the relative content of α-globulins increases and the relative content of β-globulins in the blood serum decreases, changes with urine 17-ketosteroids. With various forms of G.'s damage, disturbances in thermoregulation and sweating intensity appear. G.'s nuclei (mainly the suprasurgent and paraventricular) are most likely in diseases of the endocrine glands, traumatic brain injuries leading to redistribution of cerebrospinal fluid, tumors, neuroinfections, intoxications, etc. Due to increased permeability of the vascular walls during infections and intoxications, the hypothalamic nuclei can be exposed to pathogenic exposure to bacterial and viral toxins and chemicals circulating in the blood. Neuroviral infections are especially dangerous in this regard. G.'s lesions are observed in basal tuberculous meningitis, syphilis, sarcoidosis, lymphogranulomatosis, and leukemia.

Among G.'s tumors, the most common are various types of gliomas, craniopharyngiomas, ectopic pinealomas and teratomas, and meningiomas: suprasellar adenomas of the pituitary gland (pituitary adenoma) grow in G. . Clinical manifestations and dysfunctions and diseases of the hypothalamus - see Hypothalamic-pituitary insufficiency , Hypothalamic syndromes , Adiposogenital dystrophy , Itsenko - Cushing's disease , Diabetes insipidus , Hypogonadism , Hypothyroidism, etc.

II Hypothalamus (hypothalamus, BNA, JNA; hypo- (Hyp-) + ; ,: , subcutaneous region, )

a section of the diencephalon located downward from the thalamus and constituting the lower wall (bottom) of the third ventricle; G, secretes neurohormones and is the highest subcortical center of the autonomic nervous system.

1. Small medical encyclopedia. - M.: Medical encyclopedia. 1991-96 2. First aid. - M.: Great Russian Encyclopedia. 1994 3. Encyclopedic Dictionary of Medical Terms. - M.: Soviet Encyclopedia. - 1982-1984.

Synonyms:

See what “Hypothalamus” is in other dictionaries:

Hypothalamus... Spelling dictionary-reference book

hypothalamus- structure of the intermediate brain, located under the thalamus. Contains 12 pairs of nuclei of the most important centers of vegetative functions. Moreover, it is closely connected with the pituitary gland, whose activity it regulates. Dictionary of a practical psychologist. M.: AST, Harvest. WITH.… … Great psychological encyclopedia

HYPOTHALAMUS, a section of the diencephalon (under the thalamus), in which the centers of the autonomic nervous system are located; closely related to the pituitary gland. The hypothalamus produces neurohormones that regulate metabolism, cardiac activity... ... Modern encyclopedia

Division of the diencephalon (under the thalamus), in which the centers of the autonomic nervous system are located; closely related to the pituitary gland. The nerve cells of the hypothalamus produce the neurohormones vasopressin and oxytocin (secreted by the pituitary gland), as well as... ... Big Encyclopedic Dictionary

- (from hypo... and thalamus), part of the diencephalon; the highest center for the regulation of the body's vegetative functions and reproduction; place of interaction between the nervous and endocrine systems. Phylogenetically, G. is an ancient part of the brain, existing in all... ... Biological encyclopedic dictionary

Each person is an individual with his own habits, passions and character traits. However, few people suspect that all habits, like character traits, are features of the structure and functioning of the hypothalamus, a part of the brain. It is the hypothalamus that is responsible for all human life processes.

For example, people who get up early and go to bed late are called larks. And this feature of the body is formed thanks to the work of the hypothalamus.

Despite its tiny size, this part of the brain regulates a person’s emotional state and has a direct impact on the activity of the endocrine system. Therefore, you can understand the characteristics of the human soul if you understand the functions of the hypothalamus and its structure, as well as what processes the hypothalamus is responsible for.

What is the hypothalamus

The human brain consists of many parts, each of which performs specific functions. The hypothalamus, together with the thalamus, is a part of the brain. Despite this, both of these organs perform completely different functions. If the duties of the thalamus include transmitting signals from receptors to the cerebral cortex, the hypothalamus, on the contrary, acts on receptors located in the internal organs with the help of special hormones - neuropeptides.

The main function of the hypothalamus is to control two systems of the body - autonomic and endocrine. The correct functioning of the autonomic system allows a person not to think about when he needs to inhale or exhale, when he needs to increase blood flow in the vessels, and when, on the contrary, to slow it down. That is, the autonomic nervous system controls all automatic processes in the body with the help of two branches - sympathetic and parasympathetic.

If the functions of the hypothalamus are disrupted for any reason, a failure occurs in almost all body systems.

Location of the hypothalamus

The word "hypothalamus" consists of two parts, one of which means "under" and the other "thalamus". It follows that the hypothalamus is located in the lower part of the brain under the thalamus. It is separated from the latter by the hypothalamic groove. This organ closely interacts with the pituitary gland, forming a single hypothalamic-pituitary system.

The size of the hypothalamus may vary from person to person. However, it does not exceed 3 cm³, and its weight varies within 5 g. Despite its tiny size, the structure of the organ is quite complex.

It should be noted that the cells of the hypothalamus penetrate other parts of the brain, so it is not possible to define clear boundaries of the organ. The hypothalamus is an intermediate part of the brain, which, among other things, forms the walls and floor of the 3rd ventricle of the brain. In this case, the anterior wall of the 3rd ventricle acts as the anterior border of the hypothalamus. The border of the posterior wall runs from the posterior commissure of the fornix to the corpus callosum.

The lower part of the hypothalamus, located near the mastoid body, consists of the following structures:

• gray lump;
• mastoid bodies;
• funnels and others.

There are about 12 departments in total. The funnel starts from the gray mound, and since its middle part is slightly elevated, it is called the “median eminence.” The lower part of the infundibulum connects the pituitary gland and hypothalamus, acting as the pituitary stalk.

The structure of the hypothalamus includes three separate zones:

• periventricular or periventricular;
• medial;
• lateral.

Features of the hypothalamic nuclei

The inner part of the hypothalamus consists of nuclei - groups of neurons, each of which performs specific functions. The nuclei of the hypothalamus are a collection of neuron cell bodies (gray matter) in pathways. The number of nuclei is individual and depends on the gender of the person. On average, their number exceeds 30 pieces.

The nuclei of the hypothalamus form three groups:

• anterior, which is located in one of the areas of the optic chiasm;
• the middle one, located in the gray mound;
• posterior, which is located in the area of ​​the mastoid bodies.

Control over all human life processes, his desires, instincts and behavior is carried out by special centers located in the nuclei. For example, when one center is irritated, a person begins to feel hunger or a feeling of fullness. Irritation of another center can cause feelings of joy or sadness.

Functions of the hypothalamic nuclei

The anterior nuclei stimulate the parasympathetic nervous system. They perform the following functions:

• narrow the pupils and palpebral fissures;
• reduce heart rate;
• reduce blood pressure levels;
• enhance motility of the gastrointestinal tract;
• increase the production of gastric juice;
• increase cell sensitivity to insulin;
• influence sexual development;
• regulate heat exchange processes.

The posterior nuclei regulate the sympathetic nervous system and perform the following functions:

• I dilate the pupils and eye slits;
• increase heart rate;
• increase blood pressure in the vessels;
• reduce gastrointestinal motility;
• increase concentration in the blood;
• inhibit sexual development;
• reduce the sensitivity of tissue cells to insulin;
• increase resistance to physical stress.

The middle group of hypothalamic nuclei regulates metabolic processes and influences eating behavior.

Functions of the hypothalamus

The human body, however, like any other living creature, is capable of maintaining a certain balance even under the influence of external stimuli. This ability helps creatures survive. And it's called homeostasis. Homeostasis is maintained by the nervous and endocrine systems, the functions of which are regulated by the hypothalamus. Thanks to the coordinated work of the hypothalamus, a person is endowed with the ability not only to survive, but also to reproduce.

A special role is played by the hypothalamic-pituitary system, in which the hypothalamus is connected to the pituitary gland. Together they form a single hypothalamic-pituitary system, where the hypothalamus plays a commanding role, sending signals to the pituitary gland for action. At the same time, the pituitary gland itself receives signals coming from the nervous system and sends them to organs and tissues. Moreover, they are influenced by hormones that act on target organs.

Types of hormones

All hormones produced by the hypothalamus have a protein structure and are divided into two types:

• releasing hormones, which include statins and liberins;
• hormones of the posterior lobe of the pituitary gland.

The production of releasing hormones occurs when the activity of the pituitary gland changes. When activity decreases, the hypothalamus produces liberin hormones, designed to compensate for hormonal deficiency. If the pituitary gland, on the contrary, produces an excessive amount of hormones, the hypothalamus releases statins into the blood, which inhibit the synthesis of pituitary hormones.

Liberins include the following substances:

• gonadoliberins;
• somatoliberin;
• prolactoliberin;
• Thyroliberin;
• melanoliberin;
• corticoliberin.

The list of statins includes the following:

• somatostatin;
• melanostatin;
• prolactostatin.

Other hormones produced by the neuroendocrine regulator include oxytocin, orexin and neurotensin. These hormones enter the posterior lobe of the pituitary gland through the portal network, where they accumulate. As needed, the pituitary gland releases hormones into the blood. For example, when a young mother feeds her baby, she needs oxytocin, which, by acting on receptors, helps push milk through.

Pathologies of the hypothalamus

Depending on the characteristics of hormone synthesis, all diseases of the hypothalamus are divided into three groups:

• the first group includes diseases characterized by increased production of hormones;
• the second group includes diseases characterized by decreased production of hormones;
• The third group consists of pathologies in which the synthesis of hormones is not disrupted.

Considering the close interaction of two areas of the brain - the hypothalamus, as well as the common blood supply and features of the anatomical structure, some of their pathologies are combined into a common group.

The most common pathology is adenoma, which can form in both the hypothalamus and the pituitary gland. An adenoma is a benign formation that consists of glandular tissue and independently produces hormones.

Most often, tumors that produce somatotropin, thyrotropin and corticotropin form in these areas of the brain. For women, the most common is prolactinoma - a tumor that produces prolactin - the hormone responsible for the production of breast milk.

Another disease that often disrupts the functions of the hypothalamus and pituitary gland is. The development of this pathology not only disrupts the balance of hormones, but also causes a malfunction of the autonomic nervous system.

Various factors, both internal and external, can have a negative effect on the hypothalamus. In addition to the tumor, inflammatory processes can occur in these parts of the brain caused by viral and bacterial infections entering the body. Pathological processes can also develop as a result of bruises and strokes.

Conclusion

• since the hypothalamus regulates circardial rhythms, it is very important to maintain a daily routine, going to bed and getting up at the same time;
• Walking in the fresh air and playing sports help improve blood circulation in all parts of the brain and saturate them with oxygen;
• Quitting smoking and alcohol helps normalize the production of hormones and improve the activity of the autonomic nervous system;
• eating eggs, fatty fish, seaweed, walnuts, vegetables and dried fruits will ensure that the body receives the nutrients and vitamins necessary for the normal function of the hypothalamic-pituitary system.

Having understood what the hypothalamus is and what effect this part of the brain has on human life, we should remember that its damage leads to the development of serious diseases, which often end in death. Therefore, it is necessary to monitor your health and consult a doctor when the first ailments appear.

Hypothalamus(hypothalamus) - a section of the diencephalon, which plays a leading role in the regulation of many functions of the body, and above all the constancy of the internal environment, the hypothalamus is the highest vegetative center, carrying out the complex integration of the functions of various internal systems and their adaptation to the integral activity of the body, plays a significant role in maintaining an optimal level of metabolism and energy, in thermoregulation, in regulating the activity of the digestive, cardiovascular, excretory, respiratory and endocrine systems. Under the control of the hypothalamus are such endocrine glands as the pituitary gland, thyroid gland, gonads, pancreas, adrenal glands, etc.

The hypothalamus is located inferior to the thalamus under the hypothalamic sulcus. Its anterior border is the optic chiasma (chiasma opticum), the terminal plate (lamina terminalis) and the anterior commissure (commissura ant.). The posterior border passes behind the lower edge of the mastoid bodies (corpora mamillaria).
Anteriorly, the cell groups of the hypothalamus without interruption pass into the cell groups of the plate of the transparent septum (lamina septi pellucidi).

The pathways closely connect the hypothalamus with neighboring brain structures. The blood supply to the nuclei of the hypothalamus is carried out by branches of the arterial circle of the brain. The relationship between the hypothalamus and the adenohypophysis occurs through the portal vessels of the adenohypophysis. A characteristic feature of the blood vessels of the hypothalamus is the permeability of their walls to large protein molecules.

Despite the small size of the hypothalamus, its structure is highly complex. Groups of cells form separate nuclei of the hypothalamus. In humans and other mammals, the hypothalamus usually has 32 pairs of nuclei. Between adjacent nuclei there are intermediate nerve cells or small groups of them, so not only the nuclei, but also some internuclear hypothalamic zones may have physiological significance. The nuclei of the hypothalamus are formed by nerve cells that do not have secretory function and neurosecretory cells. Neurosecretory nerve cells are concentrated directly near the walls of the third ventricle of the brain. In their structural characteristics, these cells resemble the cells of the reticular formation and produce physiologically active substances - hypothalamic neurohormones.

The hypothalamus has three vaguely demarcated regions: anterior, middle and posterior. Neurosecretory cells are concentrated in the anterior region of the hypothalamus, where they form the supraopticus (nucl. supraopticus) and paraventricular (nucl. paraventricularis) nuclei on each side. The episodic nucleus consists of cells lying between the wall of the third ventricle of the brain and the dorsal surface of the optic chiasm. The paraventricular nucleus looks like a plate between the fornix (fornix) and the wall of the third ventricle of the brain. The axons of the neurons of the paraventricular and supravisual nuclei, forming the hypothalamic-pituitary bundle, reach the posterior lobe of the pituitary gland, where hypothalamic neurohormones accumulate, from where they enter the bloodstream.

Between the supravisual and paraventricular nuclei there are numerous single neurosecretory cells or groups of them. Neurosecretory cells of the supravisual nucleus of the hypothalamus produce predominantly antidiuretic hormone (vasopressin), and the paraventricular nucleus produces oxytocin.

In the middle region of the hypothalamus, around the lower edge of the third ventricle of the brain, lie the gray tuberous nuclei (nucll. tuberaies), arcuately covering the infundibulum of the pituitary gland. Above and slightly lateral to them are the large ventromedial and dorsomedial nuclei.

In the posterior region of the hypothalamus there are nuclei consisting of scattered large cells, among which there are clusters of small cells. This section also includes the medial and lateral nuclei of the mastoid body (nucll. corporis mamillaris mediales et laterales), which on the lower surface of the diencephalon look like paired hemispheres . The cells of these nuclei give rise to one of the so-called projection systems of the hypothalamus into the medulla oblongata and spinal cord.

The largest cell cluster is the medial nucleus of the mastoid body. Anterior to the mammillary bodies protrudes the bottom of the third ventricle of the brain in the form of a gray mound (tuber cinereum), formed by a thin plate of gray matter. This protrusion extends into a funnel, which passes distally into the pituitary stalk and further into the posterior lobe of the pituitary gland. The expanded upper part of the funnel - the median eminence - is lined with ependyma, followed by a layer of nerve fibers of the hypothalamic-pituitary fascicle and thinner fibers originating from the nuclei of the gray tuberosity.

The outer part of the median eminence is formed by supporting neuroglial (ependymal) fibers, between which numerous nerve fibers lie. Deposition of neurosecretory granules is observed in and around these nerve fibers. Thus, the hypothalamus is formed by a complex of nerve conduction and neurosecretory cells. In this regard, the regulatory influences of the hypothalamus are transmitted to effectors, incl. and to the endocrine glands, not only with the help of hypothalamic neurohormones carried by the bloodstream and, therefore, acting humorally, but also along efferent nerve fibers.

The hypothalamus plays a significant role in the regulation and coordination of the functions of the autonomic nervous system. The nuclei of the posterior region of the hypothalamus participate in the regulation of the function of its sympathetic part, and the functions of the parasympathetic part of the autonomic nervous system are regulated by the nuclei of its anterior and middle regions. Stimulation of the anterior and middle regions of the hypothalamus causes reactions characteristic of the parasympathetic nervous system - a decrease in heart rate, increased intestinal motility, increased bladder tone, etc., and irritation of the posterior region of the hypothalamus is manifested by an increase in sympathetic reactions - increased heart rate, etc.

Vasomotor reactions of hypothalamic origin are closely related to the state of the autonomic nervous system. Various types of arterial hypertension that develop after stimulation of the hypothalamus are due to the combined influence of the sympathetic part of the autonomic nervous system and the release of adrenaline by the adrenal glands, although in this case the influence of the neurohypophysis cannot be excluded, especially in the genesis of stable arterial hypertension.

From a physiological point of view, the hypothalamus has a number of features, primarily this concerns its participation in the formation of behavioral reactions that are important for maintaining the constancy of the internal environment of the body. Irritation of the hypothalamus leads to the formation of purposeful behavior - eating, drinking, sexual, aggressive, etc. The hypothalamus plays a major role in the formation of the body's basic drives.

In some cases, when the superomedial nucleus and gray-tuberous region of G. are damaged, excessive obesity is observed as a result of polyphagia (bulimia) or cachexia. Damage to the posterior hypothalamus causes hyperglycemia. The role of the suprasensory and paraventricular nuclei in the mechanism of diabetes insipidus has been established. Activation of neurons in the lateral hypothalamus causes the formation of food motivation. With bilateral destruction of this section, food motivation is completely eliminated.

Extensive connections of the hypothalamus with other structures of the brain contribute to the generalization of excitations that arise in its cells. The hypothalamus is in continuous interaction with other parts of the subcortex and the cerebral cortex. This is what underlies the participation of the hypothalamus in emotional activity. The cerebral cortex may have an inhibitory effect on the functions of the hypothalamus. Acquired cortical mechanisms suppress many emotions and primary impulses that are formed with its participation. Therefore, decortication often leads to the development of an “imaginary rage” reaction (pupil dilation, tachycardia, development of intracranial hypertension, increased salivation, etc.).

The hypothalamus is one of the main structures involved in the regulation of sleep and wakefulness. Clinical studies have established that the symptom of lethargic sleep in epidemic encephalitis is caused precisely by damage to the hypothalamus. The posterior region of the hypothalamus plays a decisive role in maintaining a state of wakefulness. Extensive destruction of the middle region of the hypothalamus in the experiment led to the development of long-term sleep. Sleep disturbance in the form of narcolepsy is explained by damage to the hypothalamus and the rostral part of the reticular formation of the midbrain.

The hypothalamus plays an important role in thermoregulation. Destruction of the posterior parts of the hypothalamus leads to a persistent decrease in body temperature.

The cells of the hypothalamus have the ability to transform humoral changes in the internal environment of the body into a nervous process. The centers of the hypothalamus are characterized by pronounced selectivity of excitation depending on various changes in blood composition and acid-base state, as well as nerve impulses from the corresponding organs. Excitation in the neurons of the hypothalamus, which have selective reception in relation to blood constants, does not occur immediately as soon as any of them changes, but after a certain period of time.

If the change in the blood constant is maintained for a long time, then in this case the excitability of the hypothalamic neurons quickly rises to a critical value and the state of this excitation is maintained at a high level as long as the change in the constant exists. Excitation of some cells of the hypothalamus can occur periodically after a few hours, as, for example, during hypoglycemia, others - after several days or even months, as, for example, when the content of sex hormones in the blood changes.

Informative methods for studying the hypothalamus are plethysmographic, biochemical, x-ray studies, etc. Plethysmographic studies reveal a wide range of changes in the hypothalamus - from a state of autonomic vascular instability and paradoxical reaction to complete areflexia.

In biochemical studies in patients with damage to the hypothalamus, regardless of its cause (tumor, inflammatory process, etc.), an increase in the content of catecholamines and histamine in the blood is often determined, the relative content of a-globulins increases and the relative content of b-globulins in the blood serum decreases, excretion changes with urine 17-ketosteroids. With various forms of damage to the hypothalamus, disturbances in thermoregulation and sweating intensity appear.

Damage to the nuclei of the hypothalamus (mainly the supraocular and paraventricular) is most likely in diseases of the endocrine glands, traumatic brain injuries leading to redistribution of cerebrospinal fluid, tumors, neuroinfections, intoxications, etc. Due to increased permeability of the vascular walls during infections and intoxications, the hypothalamic nuclei can be exposed to pathogenic exposure to bacterial and viral toxins and chemicals circulating in the blood. Neuroviral infections are especially dangerous in this regard. Hypothalamic lesions are observed in basal tuberculous meningitis, syphilis, sarcoidosis, lymphogranulomatosis, and leukemia.

Of the hypothalamic tumors, the most common are various types of gliomas, craniopharyngiomas, ectopic pinealomas and teratomas, meningiomas: suprasellar pituitary adenomas grow in the hypothalamus. Clinical manifestations and treatment of dysfunctions and diseases of the hypothalamus