Inside it is the cavity of the third cerebral ventricle. The diencephalon consists of:

1. visual brain

   • thalamus

   • Epithalamus (suprathalamic region - epiphysis, leashes, commissure of leashes, triangles of leashes)

   • Metathalamus (zathalamic region - medial and lateral geniculate bodies)

2. Hypothalamus (subthalamic region)

• Anterior hypothalamic region (visual - optic chiasm, tract)

• Intermediate hypothalamic region (gray tubercle, infundibulum, pituitary gland)

• Posterior hypothalamic region (papillary bodies)

• Proper subthalamic region (Posterior hypothalamic nucleus of Luisi)

thalamus

The visual hillock consists of gray matter, divided by layers of white matter into separate nuclei. The fibers originating from them form a radiant crown that connects the thalamus with other parts of the brain.

The thalamus is the collector of all afferent (sensory) pathways leading to the cerebral cortex. This is the gate on the way to the cortex, through which all information from the receptors passes.

thalamus nuclei:

1. Specific - switching afferent impulses to strictly localized areas of the cortex.

1.1. Relay (switching)

1.1.1.Touch(ventral posterior, ventral intermediate nucleus) switching of afferent impulses to sensory areas of the cortex.

1.1.2.Non-sensory - switching non-sensory information to the cortex.

• limbic nuclei(anterior nuclei) - subcortical center of smell. Anterior nuclei of the thalamus limbic cortex-hippocampus-hypothalamus-mamillary bodies of the hypothalamus - the anterior nuclei of the thalamus (Peypets reverb circle - the formation of emotions).
• Motor cores: (ventral) switch impulses from the basal ganglia, the dentate nucleus of the cerebellum, the red nucleus to motor and premotor area(transmission of complex motor programs formed in the cerebellum and basal ganglia).

1.2. Associative (integrative function, receive information from other nuclei of the thalamus, send impulses to the associative areas of the KGM, there is feedback)

1.2.1. Pillow nuclei - impulses from the geniculate bodies and non-specific nuclei of the thalamus, to the temporal-parietal-occipital zones of the CGM, involved in gnostic, speech and visual reactions (integration of a word with a visual image), perception of the body scheme. Electrical stimulation of the pillow leads to a violation of the naming of objects, the destruction of the pillow - a violation of the body scheme, eliminates severe pain.

1.2.2. Mediodorsal nucleus - from the hypothalamus, amygdala, hippocampus, thalamic nuclei, central gray matter of the trunk, to the associative frontal and limbic cortex. Formation of emotions and behavioral motor activity, participation in memory mechanisms. Destruction - eliminates fear, anxiety, tension, suffering from pain, but decreases initiative, indifference, hypokinesia.

1.2.3. Lateral nuclei - from the geniculate bodies, the ventral nucleus of the thalamus, to the parietal cortex (gnosis, praxis, body scheme.)

1. Nonspecific nuclei - (intralaminar nuclei, reticular nucleus) signaling in all sections of KGM. Numerous incoming and outgoing fibers, an analogue of the RF stem - an integrating role between the brainstem, cerebellum and basal ganglia, neonatal and limbic cortex. Modulating influence, provide fine regulation of behavior, "smooth tuning" of GNI.

Metathalamus The medial geniculate bodies together with the inferior tubercles of the quadrigemina of the midbrain form the subcortical center of hearing. They play the role of switching centers for nerve impulses sent to the cerebral cortex. On the neurons of the nucleus of the medial geniculate body, the fibers of the lateral loop end. The lateral geniculate bodies, together with the superior tubercles of the quadrigemina and the pillow of the thalamus, are the subcortical centers of vision. They are communication centers at which the visual tract ends, and in which the paths that conduct nerve impulses to the visual centers of the cerebral cortex are interrupted.

Epithalamus The pineal gland is associated with the parietal organ of some higher fish and reptiles. In cyclostomes, it retained to a certain extent the structure of the eye; in anurans, it is found in a reduced form under the scalp. In mammals and humans, the pineal gland has a glandular structure and is an endocrine gland (hormone - melatonin).

The epiphysis (pineal gland) refers to the glands of internal secretion. It produces serotonin, from which melatonin is then formed. The latter is an antagonist of melanocyte-stimulating hormone of the pituitary gland, as well as sex hormones. The activity of the pineal gland depends on the illumination, i.e. the circadian rhythm is manifested, and this regulates the reproductive function of the body.

Hypothalamus

The hypothalamic region contains forty-two pairs of nuclei, which are divided into four groups: anterior, intermediate, posterior, and dorsolateral.

The hypothalamus is the ventral part of the diencephalon, anatomically consists of the preoptic region, the region of the optic chiasm, the gray tubercle and infundibulum, and the mastoid bodies. The following groups of nuclei are distinguished:

• Anterior group of nuclei (anterior to the gray nucleus) - preoptic nuclei, suprachiasmatic, supraoptic, paraventricular
• Intermediate (tuberal) group (in the region of the gray tubercle and infundibulum) - dorsomedial, ventromedial, arcuate (infundibular), dorsal hypotuberous, posterior PVN and own nuclei of the tubercle and infundibulum. The first two groups of nuclei are neurosecretory.
• Posterior - the nuclei of the papillary bodies (subcortical center of smell)
• Subthalamic nucleus of Louis (integration function

The hypothalamus has the most powerful network of capillaries in the brain and the highest level of local blood flow (up to 2900 capillaries per mm square). Capillary permeability is high, because The hypothalamus has cells that are selectively sensitive to changes in blood parameters: changes in pH, the content of potassium and sodium ions, oxygen tension, carbon dioxide. The supraoptic nucleus has osmoreceptors, the ventromedial nucleus has chemoreceptors glucose-sensitive in the anterior hypothalamus sex hormone receptors. There is thermoreceptors. The sensitive neurons of the hypothalamus do not adapt, and are excited until one or another constant in the body returns to normal. The hypothalamus carries out efferent influences with the help of the sympathetic and parasympathetic nervous systems, and endocrine glands. Here are the centers of regulation of various types of metabolism: protein, carbohydrate, fat, mineral, water, as well as centers of hunger, thirst, satiety, pleasure. The hypothalamic region is referred to the higher subcortical centers of autonomic regulation. Together with the pituitary gland, it forms the hypothalamic-pituitary system, through which the nervous and hormonal regulation is interfaced in the body.

In the hypothalamic region, endorphins and enkephalins are synthesized, which are part of the natural pain system and affect the human psyche.

Nerve pathways to the hypothalamus come from the limbic system, CGM, basal ganglia, RF trunk. From the hypothalamus to the Russian Federation, the motor and autonomic centers of the trunk to the autonomic centers of the spinal cord, from the mammillary bodies to the anterior nuclei of the thalamus, then to the limbic system, from the SOYA and PVN to the neurohypophysis, from the ventromedial and infundibular to the adenohypophysis, there are also connections with the frontal cortex and striped body.

Hormones SOYA and PVN:

1. ADH (vasopressin)
2. Oxytocin

Hormones of the mediobasal hypothalamus: ventromedial and infundibular nuclei:

1. Liberins (releasing) corticoliberin, thyroliberin, luliberin, folliberin, somatoliberin, prolactoliberin, melanoliberin

2. Statins (inhibins) somatostatin, prolactostatin and melanostatin

Functions:

1. Maintenance of homeostasis
2. Integrative Center for Autonomic Functions
3. High Endocrine Center
4. Regulation of heat balance (front nuclei - the center of heat transfer, rear - the center of heat generation)
5. Regulator of the sleep-wake cycle and other biorhythms
6. Role in eating behavior (middle group of nuclei: lateral nucleus - hunger center and ventromedial nucleus - satiety center)
7. Role in sexual, aggressive-defensive behavior. Irritation of the anterior nuclei stimulates sexual behavior, irritation of the posterior nuclei inhibits sexual development.
8. Center for the regulation of various types of metabolism: protein, carbohydrate, fat, mineral, water.
9. It is an element of the antinociceptive system (pleasure center)

diencephalon in the process of embryogenesis develops from the anterior cerebral bladder. It forms the walls of the third cerebral ventricle. The diencephalon is located under the corpus callosum and consists of the thalamus, epithalamus, metathalamus, and hypothalamus.

Thalamus (optical tubercles) are a cluster having an ovoid shape. The thalamus is a large subcortical formation through which a variety of afferent pathways pass into the cortex. Its nerve cells are grouped into a large number of nuclei (up to 40). Topographically, the latter are divided into anterior, posterior, median, medial and lateral groups. By function, the thalamic nuclei can be differentiated into specific, nonspecific, associative and motor.

From specific nuclei, information about the nature of sensory stimuli enters strictly defined areas of 3-4 layers of the cortex. The functional basic unit of the specific thalamic nuclei are the "relay" ones, which have few dendrites, are long and perform a switching function. Here, the pathways leading to the cortex from skin, muscle and other types of sensitivity are switched. Violation of the function of specific nuclei leads to the loss of specific types of sensitivity.

Nonspecific nuclei of the thalamus are associated with many parts of the cortex and take part in the activation of its activity, they are referred to.

The associative nuclei are formed by multipolar, bipolar neurons, the axons of which go to the 1st and 2nd layers, and partly of the projection areas, giving off to the 4th and 5th layers of the cortex along the way, forming associative contacts with pyramidal neurons. Associative nuclei are associated with the nuclei of the cerebral hemispheres, the hypothalamus, the middle and. Associative nuclei are involved in higher integrative processes, but their functions have not yet been studied enough.

The motor nuclei of the thalamus include the ventral nucleus, which has an input from the basal ganglia, and at the same time gives projections into the motor zone of the cerebral cortex. This core is included in the movement regulation system.

The thalamus is a structure in which the processing and integration of almost all signals going to the cerebral cortex from neurons, the cerebellum takes place. The ability to obtain information about the state of many body systems allows it to participate in the regulation and determine the body as a whole. This is confirmed by the fact that there are about 120 differently functional nuclei in the thalamus.

The functional significance of the thalamic nuclei is determined not only by their projection onto other brain structures, but also by what structures send their information to it. Signals come to the thalamus from the visual, auditory, gustatory, skin, muscular systems, from the nuclei of the cranial nerves, the trunk, cerebellum, and oblongata. In this regard, the thalamus is actually a subcortical sensory center. The processes of thalamic neurons are directed partly to the nuclei of the striatum of the telencephalon (in this regard, the thalamus is considered as a sensitive center of the extrapyramidal system), partly to the cerebral cortex, forming thalamocortical pathways.

Thus, the thalamus is the subcortical center of all types of sensitivity, except for the olfactory one. The ascending (afferent) pathways, along which information is transmitted from various ones, are approached and switched. Nerve fibers go from the thalamus to the cerebral cortex, making up the thalamocortical bundles.

Hypothalamus- phylogenetic old part of the diencephalon, which plays an important role in maintaining the constancy of the internal environment and ensuring the integration of the functions of the autonomic, endocrine and somatic systems. The hypothalamus is involved in the formation of the bottom of the third ventricle. The hypothalamus includes the optic chiasm, the optic tract, the gray tubercle with a funnel, and the mastoid body. The structures of the hypothalamus have a different origin. The visual part (optic chiasm, optic tract, gray tubercle with a funnel, neurohypophysis) is formed from the telencephalon, and the olfactory part (mastoid body and hypothalamus) is formed from the intermediate brain.

The optic chiasm has the form of a transversely lying roller, formed by the fibers of the optic nerves (II pair), partially passing to the opposite side. This roller on each side laterally and posteriorly continues into the optic tract, which runs behind the anterior perforated substance, goes around the brain stem from the lateral side and ends with two roots in the subcortical centers. The larger lateral root approaches the lateral geniculate body, while the thinner medial root leads to the superior colliculus of the roof.

To the anterior surface of the optic chiasm, the terminal (boundary, or terminal) plate, which belongs to the telencephalon, is adjacent and fuses with it. It closes the anterior part of the longitudinal fissure of the large brain and consists of a thin layer of gray matter, which in the lateral parts of the plate continues into the substance of the frontal lobes of the hemispheres.

Functions and connections of the thalamus.

thalamus(lat. Thalamus, Latin pronunciation: thalamus; from the Greek θάλαμος - “hillock”) - an area of ​​​​the brain responsible for the redistribution of information from the senses, with the exception of smell, to the cerebral cortex. This information (impulses) enters the nuclei of the thalamus. The nuclei themselves are composed of gray matter, which is formed by neurons. Each nucleus is a collection of neurons. The nuclei are separated by white matter.

Four main nuclei can be distinguished in the thalamus: a group of neurons redistributing visual information; nucleus redistributing auditory information; a core that redistributes tactile information; and a core that redistributes a sense of equilibrium and balance.

After information about any sensation has entered the nucleus of the thalamus, its primary processing takes place there, that is, for the first time the temperature, visual image, etc. are realized. It is believed that the thalamus plays an important role in the implementation of memorization processes. Fixation of information is carried out as follows: the first stage of engram formation occurs in the SS. It begins when a stimulus excites peripheral receptors. From them, along the pathways, nerve impulses go to the thalamus, and then to the cortical region. It carries out the highest synthesis of sensation. Damage to the thalamus can lead to anterograde amnesia as well as tremors—involuntary shaking of the extremities at rest—although these symptoms are absent when the patient is consciously performing the movements.

The thalamus is associated with a rare disease called fatal familial insomnia.

The thalamus is an integrative structure of the central nervous system. There is a multilevel system of integrative processes in the thalamus, which not only ensures the conduction of afferent impulses to the cerebral cortex, but also performs many other functions that allow coordinated, albeit simple, reactions of the body, which are manifested even in thalamic animals. It is important that the process of inhibition plays the main role in all forms of integrative processes in the thalamus.
The integrative processes of the thalamus are multilevel in nature.
The first level of integration in the thalamus is carried out in the glomeruli. The basis of the glomerulus is the dendrite of the relay neuron and presynaptic processes of several types: terminals of ascending afferent and corticothalamic fibers, as well as axons of interneurons (cells of the Golgi II type). The direction of synaptic transmission in glomeruli is subject to strict laws. In a limited group of synaptic formations of the glomerulus, a collision of heterogeneous afferentations is possible. Several glomeruli located on adjacent neurons can interact with each other due to small axon-free elements, in which the rosettes of the terminals of the dendrites of one cell are part of several glomeruli. It is believed that the association of neurons into ensembles using such axon-free elements or using dendro-dendritic synapses, which are found in the thalamus, may be the basis for maintaining synchronization in a limited population of thalamic neurons.
The second, more complex, internuclear level of integration is the unification of a significant group of neurons in the thalamic nucleus with the help of its own (intranuclear) inhibitory interneurons. Each inhibitory interneuron establishes inhibitory contacts with many relay neurons. In absolute terms, the number of interneurons to the number of relay cells is 1:3 (4), but due to the overlap of mutual inhibitory interneurons, such ratios are created when one interneuron is associated with tens and even hundreds of relay neurons. Any excitation of such an intercalary neuron leads to inhibition of a significant group of relay neurons, as a result of which their activity is synchronized. At this level of integration, great importance is attached to inhibition, which provides control of the afferent input to the nucleus and which is probably most represented in the relay nuclei.
The third level of integrative processes occurring in the thalamus without the participation of the cerebral cortex is represented by the intrathalamic level of integration. The reticular nucleus (n. R) and the ventral anterior nucleus (n. VA) of the thalamus play a decisive role in these processes; other nonspecific thalamic nuclei are also assumed to be involved. Intrathalamic integration is also based on the processes of inhibition, which are carried out due to long axonal systems, the bodies of neurons of which are located in the reticular nucleus and, possibly, in other nonspecific nuclei. Most of the axons of the thalamocortical neurons of the relay nuclei of the thalamus pass through the neuropil of the reticular nucleus of the thalamus (covering the thalamus from almost all sides), giving it collaterals. It is assumed that neurons n. R carry out recurrent inhibition of thalamocortical neurons of the relay nuclei of the thalamus.
In addition to controlling thalamocortical conduction, intranuclear and intrathalamic integrative processes may be important for certain specific thalamic nuclei. Thus, intranuclear inhibitory mechanisms can provide discriminatory processes, enhancing the contrast between excited and intact areas of the receptive field. It is assumed that the reticular nucleus of the thalamus is involved in providing focused attention. This nucleus, thanks to the wide-branched network of its axons, can inhibit the neurons of those relay nuclei to which the afferent signal is not addressed at the moment.
The fourth, highest level of integration, in which the nuclei of the thalamus take part, is the thalamocortical. Corticofugal impulses play an important role in the activity of the thalamic nuclei, controlling conduction and many other functions, from the activity of synaptic glomeruli to systems of neuronal populations. The effect of cortico-fugal impulses on the activity of neurons in the thalamic nuclei has a phase character: at first, thalamocortical conduction is relieved for a short period (up to 20 ms on average), and then inhibition occurs for a relatively long period (up to 150 ms on average). The tonic effect of cortico-fugal impulsation is also allowed. Due to the connections of thalamic neurons with various areas of the cerebral cortex and feedback, a complex system of thalamocortical relationships is established.
The thalamus, realizing its integrative function, takes part in the following processes:
1. All sensory signals, except those arising in the olfactory sensory system, reach the cortex through the nuclei of the thalamus and are recognized there.
2. The thalamus is one of the sources of rhythmic activity in the cerebral cortex.
3. The thalamus is involved in the processes of the sleep-wake cycle.
4. The thalamus is the center of pain sensitivity.
5. The thalamus takes part in the organization of various types of behavior, in memory processes, in the organization of emotions, etc.

The development of psychiatry and neurology in modern conditions is impossible without deep knowledge of the structure and functions of the brain. Without understanding the processes occurring in this organ, it is impossible to effectively treat diseases and return people to a full life. Violations at any stage of embryogenesis - genetic anomalies or disorders due to teratogenic influences of external factors - lead to the development of organic pathologies and irreparable consequences.

important department

The brain is a complex structure of the body. It includes various elements. One of the most important departments is considered intermediate. It includes several links: thalamus, hypothalamus, epithalamus and metethalamus. The first two are the most important.

Thalamus: physiology

This element is presented as a median symmetrical formation. It is located between the midbrain and the cortex. The element consists of 2 departments. The thalamus is part of the limbic system. It performs various tasks. During the period of embryonic development, this element is considered the largest. It is fixed in the so-called anterior region, near the center of the brain. Nerve fibers extend from it into the cortex in all directions. The medial surface forms the lateral wall in the third ventricle.

Nuclei

The thalamus is part of a complex complex. It is formed from four parts. These include: hypothalamus, epithalamus, prethalamus, and dorsal thalamus. The last two are derived from an intermediate structure. The epithalamus consists of the pineal gland, the triangle, and the leashes. In this area are the nuclei involved in the activation of the sense of smell. The ontogenetic nature of the epithalamus and perthalamus is different. In this regard, they are considered as separate entities. In general, it includes more than 80 cores.

Specificity

The thalamus of the brain includes a system of lamellae. It is formed by myelinated fibers and separates the different parts of the formation. Other areas are defined by neural groups. For example, intralaminar elements, periventricular nucleus and so on. The structure of the elements differs significantly from the main thalamic part.

Classification

Each center has its own nuclei. This determines their importance for the human body. The classification of nuclei is carried out depending on their localization. The following groups are distinguished:

1. Front.
2. Mediodorsal.
3. Middle line.
4. Dorsolateral.
5. Ventrolateral.
6. Ventral posteromedial.
7. back.
8. Intralaminar.

In addition, the nuclei are divided depending on the direction of action of neurons into:

1. Visual.
2. Carrying out the processing of tactile signals.
3. Auditory.
4. Regulating balance.

Center types

There are relay, non-specific and associative nuclei. The latter include a huge number of median and intralaminar formations. The relay nuclei receive signals that are subsequently projected to different parts of the cortex. These include formations that transmit primary sensations (ventral-posterior-medial, ventral-postlateral, medial and lateral geniculate), as well as those involved in the feedback of cerebellar impulses (lateral ventral). Associative nuclei receive most of the impulses from the cortex. They project them back to regulate activity.

neural pathways

The thalamus is a structure associated with the hippocampus. The interaction is carried out through a special tract, in which there is a vault and mastoid bodies. The thalamus is connected to the cortex by thalamocortical rays. There is also a path through which information about itching, touch, temperature is transmitted. It runs through the spinal cord. There are two divisions here: ventral and lateral. On the first pass impulses about pain and temperature, on the second - about pressure and touch.

blood supply

It is carried out from the connecting posterior, inferolateral, lateral and middle choroidal, as well as paramedial thalamic-hypothalamic arterial vessels. Some people have an anatomical anomaly. It is presented in the form of the artery of Percheron. In this case, one trunk leaves. It provides blood to the entire thalamus. This phenomenon is quite rare.

Functions

What is the thalamus responsible for?? This education fulfills many tasks. In general, the thalamus is a kind of information concentrator. Through it, relaying occurs between various subcortical regions. For example, each sensory system, except for the olfactory one, uses the thalamic nuclei, which receive and transmit signals to the corresponding primary areas. For the visual area, incoming impulses from the retina are sent to the lateral regions through a center that projects information to the corresponding cortical area in the occipital sector. A special role belongs to the thalamus in the regulation of wakefulness and sleep. The nuclei interacting with the cortex form specific chains associated with consciousness. Activity and arousal are also regulated by the thalamus. Damage to this formation usually leads to coma. The thalamus is associated with the hippocampus and performs certain tasks in the organization of memory. It is believed that its areas are connected to some mesio-temporal areas. Due to this, the differentiation of familiar and recollective memory is ensured. In addition, there are suggestions that the thalamus is also involved in the neural processes necessary for motor regulation.

Pathologies

As a result of a stroke, thalamic syndrome may develop. It is manifested by unilateral burning (heat), aching sensations. It is often accompanied by mood swings. Bilateral ischemia of the thalamic region can provoke quite serious disorders. These include, for example, oculomotor disorders. With blockage of the Percheron artery, a bilateral infarction can occur.

Reticular formation of the thalamus

In the central section of the trunk is an accumulation of cells. They are intertwined with a huge number of fibers extending in all directions. When viewed under a microscope, this formation looks like a network. Therefore, it was called the reticular formation. Neuronal fibers extend to the cortex and form non-specific pathways. With their help, activity is maintained in all parts of the central nervous system. Under the influence of the formation, reflexes are amplified. In this cluster there is a selection of information. Only new and important information enters the overlying areas. The activity of the formation is always at a high level, since signals from all receptors go through it.

Neurons

They show high sensitivity to pharmacological agents and hormones. Drugs such as "Reserpine", "Aminazine", "Serpasil" and others can reduce the activity of the formation. In neurons, there is an interaction of ascending and descending signals. The impulses are in constant circulation in the circuits. This keeps the activity going. It, in turn, is necessary to maintain the tone of the nervous system. In the event of destruction of the formation, especially its upper sections, deep sleep sets in, although afferent signals continue to enter the cortex through other paths.

Each person is a person 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 - part of the brain. It is the hypothalamus that is responsible for all human life processes.

For example, people who get up early and stay up late are called early risers. And this feature of the body is formed due to the work of the hypothalamus.

Despite its meager size, this part of the brain regulates the emotional state of a person and has a direct impact on the activity of the endocrine system. Therefore, you can understand the features 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 certain functions. The hypothalamus, together with the thalamus, is part of the brain. Despite this, both of these organs perform completely different functions. If the duties of the thalamus include the transmission of 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 vegetative 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 violated for any reason, a failure occurs in almost all body systems.

Location of the hypothalamus

The word "hypothalamus" has two parts, one meaning "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, making up a single hypothalamic-pituitary system.

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

It should be noted that the cells of the hypothalamus penetrate into other parts of the brain, so it is not possible to identify clear boundaries of the organ. The hypothalamus is an intermediate part of the brain, which, among other things, forms the walls and bottom 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 mound;
• mastoid bodies;
• funnels and others.

In total there are about 12 departments. The funnel starts from a gray tubercle, and since its middle part rises slightly, it is called the "median elevation". The lower part of the infundibulum connects the pituitary 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 certain functions. The nuclei of the hypothalamus are an accumulation of bodies of neurons (gray matter) in the 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 sections of the optic chiasm;
• middle, located in a gray hillock;
• back, which is located in the region of the mastoid bodies.

Control over all life processes of a person, 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 a feeling of joy or sadness.

Functions of the hypothalamic nuclei

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

• constrict pupils and palpebral fissures;
• reduce the heart rate;
• reduce the level of blood pressure;
• increase the motility of the gastrointestinal tract;
• increase the production of gastric juice;
• increase the susceptibility of cells to insulin;
• affect sexual development;
• regulate heat exchange processes.

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

• dilate pupils and palpebral fissures;
• increase heart rate;
• increase blood pressure in the vessels;
• reduce the motility of the gastrointestinal tract;
• increase the concentration in the blood;
• inhibit sexual development;
• reduce the susceptibility of tissue cells to insulin;
• increase resistance to physical stress.

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

Functions of the hypothalamus

The human body, however, like any other living being, is able to maintain 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, whose functions 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 associated with the pituitary gland. Together they make up 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 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;
• posterior pituitary hormones.

The production of releasing hormones is carried out when the activity of the pituitary gland changes. With a decrease in activity, 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 travel through the portal network to the posterior pituitary gland, 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 to push milk.

Pathologies of the hypothalamus

Depending on the characteristics of the synthesis of hormones, 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 reduced production of hormones;
• the third group consists of pathologies in which the synthesis of hormones is not disturbed.

Given the close interaction of two parts 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 an adenoma, which can form both in the hypothalamus and in the pituitary gland. An adenoma is a benign formation that consists of glandular tissue and independently produces hormones.

Most often, tumors producing somatotropin, thyrotropin and corticotropin are formed in these areas of the brain. For women, the most characteristic 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 due to bruises and strokes.

Conclusion

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

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