What is the pituitary gland and hypothalamus, what is the connection between these parts of the brain? They make up the hypothalamic-pituitary complex, which is responsible for the normal and coordinated functioning of the entire body. Where is this part of the brain located, what is its anatomy, histology, structure and functions? What each part of the hypothalamus is responsible for (what it is is described in detail by Wikipedia).
The hypothalamus is a small area located in the diencephalon. It consists of a large number of groups of cells - nuclei. This part of the brain is a very important center that is connected to many parts of the central nervous system. These include the spinal cord, cortex and brain stem, hippocampus, amygdala and others. This section is located below the thalamus, which is why it got its name. It is located slightly higher relative to the brain stem.
The hypothalamus is located in a part that is separated from the thalamus by the hypothalamic sulcus. At the same time, its boundaries are quite unclear, which is explained by the fact that some group of cells extend into neighboring areas, while another is characterized by uncertainty in terminology. Despite this ambiguity, it is believed that this section is located between the upper brain and the lamina terminalis, anterior commissure, and optic chiasm.
Structure
The anatomy of this part of the brain implies the division into sections of the hypothalamus, of which there are 12 pieces. These include the area of the gray tuberosity, mastoid bodies and others. The nuclei of the hypothalamus are a group of neurons that perform certain functions in the human body. Their number exceeds 30 pieces. Mostly the nuclei of the hypothalamus are paired.
Anatomy and histology, for the convenience of studying these structures, divides them into zones:
- periventricular or periventricular;
- medial;
- lateral.
The periventricular zone is a thin strip that is located near the third ventricle. In the medial part, the nuclei of the hypothalamus are grouped into several areas located in the anteroposterior direction. The preoptic zone also belongs to this section, although it is more logical to attribute it to the forebrain.
In the lower region of the hypothalamus, parts such as the mammillary bodies, the infundibulum (its middle part is elevated and is called the median eminence) and the gray tubercle are distinguished. This division is not unambiguous and quite controversial, but is often used in the medical literature. The medial eminence of the hypothalamus contains a large number of blood vessels. They ensure the transfer of all produced substances to the pituitary gland, which is thus connected to the hypothalamus. The lower part of the funnel connects to the pedicle of the pituitary gland.
The activity of the hypothalamus through the pituitary gland makes it possible to effectively connect the nervous and endocrine systems. This function is possible due to the release of both hormones and neuropeptides. The nuclear zones that are capable of producing these substances are called the pituitary region. They contain neurons that can secrete certain hormones.
Nuclear structures
The activity of the hypothalamus, whose structure is quite complex, is ensured by the joint work of all nuclei. It is almost impossible to identify the zones responsible for certain functions in the human body. Only the supraoptic and paraventricular nuclei have neurons, the processes of which go to the pituitary gland, and their neurosecretion ensures the production of oxytocin and vasopressin. A feature of the lateral zone is that it does not have separate nuclear regions. Neurons are located around the medial forebrain bundle (diffuse distribution).
The group of nuclei of the chiasmatic region includes the anterior hypothalamic, supraoptic, paraventricular and others, and the periventricular is located in the periventricular zone. Near the gray tuberosity, the ventromedial, dorsomedial and arcuate neuronal clusters are distinguished. The bundle located in this area, called the lateral gray tuberous nucleus, is clearly developed exclusively in humans and higher primates. There is also a tuberomammillary complex, which is divided into several parts.
Hormonal function
When studying the hypothalamus, whose functions are the neuroendocrine regulation of the body, it is clear that it influences the pituitary gland in a certain way. It, in turn, secretes hormones that regulate the activity of many organs, glands and systems.
Release factors occur in the hypothalamic nuclei. Subsequently, they move along the axons to the pituitary gland, where they are stored for a certain time and released into the blood when necessary. Hormones produced in this area include:
- somatotropin;
- corticotropin;
- somatostatin.
Neurotensin, orexin, vasopressin are produced in the zone of the median eminence by neurosecretory cells of the hypothalamus. Also, all hormones that are secreted in this part of the brain are divided into liberins and statins. The former affect the pituitary gland, awakening its functioning. Statins have the opposite effect. On the contrary, they lower the level of certain hormones.
Functions
When the hypothalamus is exposed to certain stimuli, its neuroendocrine function is observed, which is as follows:
- maintains some vital parameters in the body - body temperature, energy and acid-base balance;
- provides homeostasis, which consists in maintaining the constancy of the internal state of the body when exposed to any environmental factors. This allows a person to survive in unfavorable conditions;
- regulates the activity of the nervous and endocrine systems;
- there is an influence on behavior that helps a person survive. These functions include ensuring memory, the desire to obtain food, care for offspring, and reproduce;
- this part of the brain quickly receives information about the composition and temperature of blood and cerebrospinal fluid, collects signals from the senses, due to which behavior is adjusted, and corresponding reactions of the autonomic nervous system are observed;
- is responsible for the presence of daily and seasonal rhythms of the body’s activity due to the reaction to light, its amount throughout the day;
- regulates appetite;
- establishes the sexual orientation of men and women.
Disruption of this part of the brain
Disruption of the normal functioning of this part of the brain may be associated with the formation of a tumor, injury or inflammatory processes. Even with minor damage to the hypothalamus due to such negative factors, serious changes can be observed. The nature of the disorder may also be influenced by the duration or severity of exposure to certain pathologies. Sometimes their development can go almost unnoticed until a certain time (during tumor processes).
Against the background of the influence of certain negative processes, the following violations may be observed:
- premature puberty is explained by the hyperfunction of this part of the brain. This disease is characterized by the appearance of secondary sexual characteristics at the age of 8-9 years. The cause of this phenomenon is considered to be increased production of gonadoliberins;
- hypofunction of this part of the brain. Leads to the appearance of diabetes insipidus, which is accompanied by dehydration and too frequent urination. A decrease in vasopressin concentration provokes the development of this disease.
Also, disruption of this part of the brain can be accompanied by sleep disorders, hypothermia, poikilothermia, endocrine, emotional and autonomic disorders. Sometimes there is amnesia, complete lack of appetite and thirst, or other pathological processes.
Bibliography
- Milku, Sht.-M. Therapy of endocrine diseases
- Izard K. Human Emotions. – M., 1980.
- Freud Z. Introduction to psychoanalysis. – M., 1989.
- Popova, Yulia Female hormonal diseases. The most effective treatment methods / Yulia Popova. - M.: Krylov, 2015. - 160 p.
- Gremling S. Workshop on stress management / S. Gremling, S. Auerbach. – St. Petersburg, 2002, p. 37–44.
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:
- Therapeutic exercise and daily walks in the fresh air (especially in the evening, before bed).
- Regular and nutritious meals. A dairy-vegetable diet is preferable. Doctors advise avoiding overeating.
- Following a daily routine helps the hypothalamus enter its usual rhythm of work.
- 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
The causes of dysfunction of the hypothalamus are:
- 1 Infectious diseases, intoxication of the body.
- 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!
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- This is a small section (about 1 cm3), but important in function, which lies on the bottom and sides of the third cerebral ventricle, ventral to the thalamus. Posteriorly, the hypothalamus is adjacent to the midbrain. The superior border of the hypothalamus is formed by the lamina terminalis and the optic chiasm. The hypothalamus is located at the base of the human brain and forms the walls of the third cerebral ventricle. The walls to the base pass into a funnel, which ends with the pituitary gland (lower medullary gland). The hypothalamus is the central structure of the limbic system of the brain and performs numerous functions.
In phylogenetically more ancient animals, the hypothalamus controlled almost all life activities. The hypothalamus includes such anatomical structures as the gray tubercle, the infundibulum, which ends in the pituitary gland, and the mammillary or mastoid bodies.
The hypothalamus has a powerful blood flow system and the largest number of capillaries compared to other brain structures.
In the neutral network of the hypothalamus, several dozen nuclei can be distinguished, which are topographically divided into three groups: anterior, middle and posterior.
The nuclei of the hypothalamus form numerous connections with each other and with other structures of the central nervous system.
Main afferents: from the limbic system, cerebral cortex, basal ganglia and reticular formation of the trunk.
The main efferents: into the brain stem - into the reticular formation, motor and autonomic centers of the spinal cord, into the limbic system, into the nuclei of the thalamus, to the posterior lobe of the pituitary gland (the anterior lobe is regulated through the posterior), that is, the hypothalamus is connected with almost all structures of the brain, in including through the limbic system.
Main functions of the hypothalamus
The hypothalamus is the highest center for the integration of autonomic functions. They can be divided into several groups:
- Regulation of the pituitary gland(see cytoarchitecture of the cerebral cortex)
- Regulation of autonomic reactions, including thermoregulation and regulation of the sympathetic and parasympathetic autonomic nervous system (see autonomic nervous system).
- Regulation of biologically significant behavior: food, drinking, sexual, defensive, sleep and wakefulness cycles (see the main regulatory centers presented in the hypothalamus).
Hypothalamus I
Hypothalamus
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 pituitary adenomas (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. 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
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