The meaning of the gray bump in medical terms. hypothalamus, hypothalamus

SAVONAROLA The times of trials have come. Oh, that the Lord would arrange for me to be the first to be exposed to them! The blackest ingratitude will fall to my lot, and cowardly people will do to me the same thing that the brothers did to Joseph, selling him to Egyptian merchants. Savonarola.

Indomitable Savonarola

The indomitable Savonarola In the 15th century, a divided Italy did not have the strength to fight against powerful opponents. But the war brought forward several remarkable personalities, and among them one of the main places belongs to the monk Girolamo Savonarola. FROM early years he found out

Savonarola Girolamo, Hierom. (1452–98), Italian. Catholic preacher, theologian and society. figure. Genus. in aristocratic family. Father S., a famous scientist, prepared him for a medical career and gave him an excellent education. However, the young man secretly left the house and joined the order

The hypothalamus is the ventral part of the diencephalon. It consists of a complex of formations located under the third ventricle. The hypothalamus is bounded anteriorly by the optic chiasm (chiasm), laterally by the anterior part of the subthalamus, the internal capsule, and the optic tracts extending from the chiasm. Posteriorly, the hypothalamus continues into the midbrain tegmentum.

In the hypothalamus, a larger anterolateral part and a smaller posterior part are distinguished. The anterolateral part forms the floor of the third ventricle of the brain and includes a gray tubercle, funnel with pituitary gland, optic tracts, optic chiasm, and borderline brain plate. This also includes the actual hypothalamic region - the accumulation of nuclei of the gray matter of the hypothalamus.

gray mound- this is a thin, convex from below part of the lower wall of the third ventricle, located between the optic chiasm in front and the mastoid bodies behind. Vegetative nuclei are located in the wall of the gray tubercle, which are classified as emotional zones of the brain. The thinned continuation of the anterior wall of the gray tubercle upwards and backwards is a border plate that forms the anterior wall of the third ventricle. Ventral and slightly anteriorly, a gray tubercle forms a funnel, which serves as an attachment point for the pituitary gland.

The hypothalamic region is located under the thalamus just above the gray tubercle and partly inside between its walls. From above, it is separated from the thalamus by the hypothalamic groove. The hypotuberous region contains up to 40 nuclei, the functional role of which is very important.

In the anterior-lateral part of the hypothalamus, the anterior and middle groups of the hypothalamic nuclei are distinguished. The anterior group includes the paraventricular nucleus, the preoptic nucleus, the supraoptic and suprachiasmatic nuclei.

The middle group of nuclei includes the dorsomedial and ventromedial nuclei, the nucleus of the gray tubercle and the nucleus of the funnel. The middle group of nuclei controls water, fat and carbohydrate metabolism, affects blood sugar levels, the ionic balance of the body, the permeability of blood vessels and cell membranes.

The posterior part of the hypothalamus is located between the gray tubercle and the posterior perforated substance and consists of the right and left mastoid bodies. Inside each of them, under a thin layer of white matter, there are two gray nuclei belonging to the subcortical olfactory centers.

The hypothalamus has a wide system of connections with many brain formations, which explains its participation in many behavioral reactions. The system of afferent and efferent fibers of the fornix connects the anterior hypothalamus and mammillary bodies with the hippocampus of the cerebral hemispheres, and the mastoid-thalamic (Vic d'Azira bundle) and mastoid-tubular pathways connect the mastoid bodies with the thalamus and the tegmentum of the midbrain.

The optic chiasm of the hypothalamus is formed when half of the fibers of the optic nerve (II pair of cranial nerves) pass to the opposite side. The optic chiasm on each side continues laterally and posteriorly into the optic tract, which is also a structure of the hypothalamus.

The intersection of the visual tracts is X-shaped, in the chiasm in primates there is a partial decussation of the fibers. Fibers from the nasal half of the retina, including the nasal half of the fovea, cross the midline and travel to the contralateral lateral geniculate body (NKT). Fibers from the temporal half of the retina, including the lateral fovea, remain on their side and are directed to the ipsilateral lateral geniculate body.

The mastoid body is a paired rounded elevation on the basis of the brain (in the hypothalamus region), in which nuclei belonging to the subcortical olfactory centers are contained under the surface layer of white matter.

46.The pituitary gland, its structure and functions. Hypothalamo-pituitary neurosecretory system.Pituitary- a brain appendage in the form of a rounded formation, located on the lower surface of the brain in a bone pocket called the Turkish saddle, produces hormones that affect growth, metabolism and reproductive function. It is the central organoendocrine system; interacts closely with the hypothalamus. The pituitary gland is located at the base of the brain (lower surface) in the pituitary fossa of the Turkish saddle-sphenoid bone-skull. The Turkish saddle is covered by a process of the hard shell of the brain - the diaphragm of the saddle, with a hole in the center through which the pituitary gland is connected to the funnel of the hypothalamus of the diencephalon; through its pituitary gland is connected with a gray tubercle located on the lower wall of the third ventricle. On the sides of the pituitary gland is surrounded by cavernous sinuses. The dimensions of the pituitary gland are quite individual: the anteroposterior / sagittal size ranges from 5 to 13 mm, the upper-lower / coronal - from 6 to 8 mm, the transverse / axial / transversal - from 3 to 5 mm. The pituitary gland consists of two large lobes of different origin and structure: the anterior - adenohypophysis (makes up 70-80% of the mass of the organ) and the posterior - neurohypophysis. Together with the neurosecretory nuclei of the hypothalamus, the pituitary gland forms the hypothalamic-pituitary system that controls the activity of the peripheral endocrine glands. Neurohypophysis (posterior pituitary gland))Neurohypophysis, neurohypophysis, comprises nerve lobe and funnels, fundibulum connecting the nerve lobe with the median eminence. The nerve lobe is formed by ependymal cells (pituicytes) and axon endings of neurosecretory cells paraventricular and supraoptic nuclei of the hypothalamus of the diencephalon, in which vasopressin (antidiuretic hormone) and oxytocin are synthesized, transported along the nerve fibers that make up the hypothalamic-pituitary tract to the neurohypophysis. In the posterior lobe of the pituitary gland, these hormones are deposited and from there they enter the bloodstream. The pituitary infundibulum joins with the hypothalamic infundibulum to form pituitary stalk. Vasopressin performs two functions in the body: 1) Increased water reabsorption in the collecting ducts of the kidneys (this is the antidiuretic function of vasopressin); 2) the effect on the smooth muscles of arterioles, however, the name "vasopressin" does not quite correspond to the property of this hormone to constrict blood vessels. The fact is that in normal physiological concentrations it does not have a vasoconstrictive effect. Vasoconstriction can occur with the exogenous introduction of the hormone in large quantities or with blood loss, when the pituitary gland intensively secretes this hormone. With insufficiency of the neurohypophysis, a syndrome of diabetes insipidus develops, in which a significant amount of water (15 l / day) can be lost in the urine per day, as its reabsorption in the collecting ducts decreases. Oxytocin during pregnancy does not affect the uterus, because under the influence of progesterone secreted by the corpus luteum, it becomes insensitive to this hormone. Oxytocin promotes the contraction of myoepithelial cells that promote the release of milk from the mammary glands. Adenohypophysis (anterior pituitary gland) Adenohypophysis, consists of glandular endocrine cells various types, each of which, as a rule, secretes one of the hormones. Anatomically, pars distalis (most of the adenohypophysis), pars tuberalis (a leaf-like outgrowth surrounding the pituitary stalk, the functions of which are not clear) and pars intermedia, which is more correctly referred to as an intermediate lobe of the pituitary gland, are distinguished in it. The anterior pituitary gland produces six hormones. The target organs of the four anterior pituitary hormones are the endocrine glands, so they are called tropic hormones. Pituitary hormones stimulate a certain gland, and an increase in the level of hormones secreted by it in the blood suppresses the secretion of the pituitary hormone. Thyroid-stimulating hormone is the main regulator of the biosynthesis and secretion of thyroid hormones. The adrenal cortex is stimulated by adrenocorticotropic hormone. The other two hormones are called gonadotropic hormones: follicle-stimulating hormone promotes the maturation of follicles in the ovaries, and luteinizing hormone causes ovulation and the formation of a corpus luteum. In addition, the anterior pituitary gland produces two more hormones that act on organ systems and the entire body as a whole. Growth hormone is the most important stimulator of protein synthesis in cells, the formation of glucose and the breakdown of fats, as well as the growth of the body. Luteotropic hormone (prolactin) regulates lactation, differentiation of various tissues, growth and metabolic processes, the instincts of caring for offspring. Intermediate (middle) lobe of the pituitary gland. At many animals have a well-developed intermediate lobe of the pituitary gland, located between the anterior and posterior lobes. It originates from the adenohypophysis. In humans, it is a thin layer of cells between the anterior and posterior lobes, which extends rather deeply into the pituitary stalk. These cells synthesize their own specific hormones. - melanocyte-stimulating and a number of others . Posterior lobe (neurohypophysis). Posterior lobe of the pituitary gland (lat. pars posterior) - endocrine organ, accumulating and secreting hormones that are synthesized in the large cell nuclei of the anterior hypothalamus and pass along the axons to the posterior pituitary gland. The neurohypophyseal hormones in mammals include: vasopressin (or antidiuretic hormone, ADH), which regulates water metabolism and arteriole tone, and also performs a mediator function in some synapses of hypothalamic neurons; oxytocin (or cytocin), which regulates the birth act and the secretion of milk by the mammary glands. In representatives of other classes of vertebrates, the posterior pituitary gland secretes other hormones that differ slightly in chemical structure and biological properties from vasopressin and oxytocin: vasotocin, mesotocin, glumitocin, isotocin, valitocin, asparotocin. The functioning of all parts of the pituitary gland is closely related to the hypothalamus. This provision applies not only to the posterior lobe - the "receiver" and depot of hypothalamic hormones, but also to the anterior and middle sections of the pituitary gland, whose work is controlled by hypothalamic pituitary hormones - releasing hormones. Hypothalamic-pituitary system- the union of the structures of the pituitary and hypothalamus, which performs the functions of both the nervous system and the endocrine system. This neuroendocrine complex is an example of how closely interconnected the nervous and humoral modes of regulation are in mammals. The hypothalamic-pituitary system consists of the pituitary stalk, which begins in the ventromedial region of the hypothalamus, and three lobes of the pituitary gland: the adenohypophysis (anterior lobe), the neurohypophysis (posterior lobe), and the intercalary lobe of the pituitary gland. The work of all three lobes is controlled by the hypothalamus with the help of special neurosecretory cells. These cells secrete special hormones called releasing hormones. The releasing factors enter the pituitary gland, more specifically the adenohypophysis, through the portal vein of the pituitary gland.

2. Hypothalamus (hypothalamus) - a relatively small, but extremely important formation of the brain. It contains nuclei containing cells responsible for regulating body temperature, various types of metabolism: water, fat, carbohydrate, etc., the activities of vital body systems (cardiovascular, digestive, vegetative, endocrine), as well as neurosecretory cells that produce many hormones.

Borders of the hypothalamus. In front, the hypothalamus borders on the optic chiasm; the posterior border is the mastoid bodies (corpora mamillaria), laterally it is limited by the visual tracts (trr. optici). The upper limit is the hypothalamic groove (sulcus hypothalamicus), which runs from the interventricular orifice (for. interventriculare) to the entrance to the cerebral aqueduct. The lower border or bottom of the third ventricle (ventriculus tertius) is represented by a gray tubercle (tuber cinereum) lying in front of the mastoid bodies. The gray tubercle extends into a funnel (infundibulum), on which the pituitary gland (hypophysis) hangs (Fig. 467).

470. Scheme of the main nuclei of the hypothalamus.
1 - chiasma opticum; 2 - nucl. supraopticus; 3 - nucl. suprachiasmaticus; 4 - nucl. preopticus; 5 - commissura cerebri anterior; 6 - nucl. paraventricularis; 7 - nucl. superomedialis; 8 - nucl. inferomedialis; 9 - nucl. corporis mamillaris; 10 - nucl. premamillaris; 11 - nucl. periventricularis; 12 - nucl. tuberis: 13 - nucl. posterior.

The mastoid bodies are paired elevations located in front of the posterior perforated substance. In the nuclei of these bodies, olfactory fibers switch, heading to the nuclei of the anterior zone of the visual tubercle, the suprathalamic region and the tegmentum of the midbrain.

The gray tubercle is a thin-walled part of the bottom of the third ventricle, located between the mastoid bodies and the optic chiasm. Anteriorly, the gray tubercle passes into a thinned end plate (lamina terminalis). It is stretched between the optic chiasm and the anterior cerebral commissure. In the nuclei of the gray hillock there are higher mechanisms of regulation of the autonomic part of the nervous system.

The visual part (pars optica) of the hypothalamus includes the optic chiasm (chiasma opticum), the right and left visual tracts (trr. optici).

The subthalamic body (corpus subthalamicum) has an oval shape, is located under the lateral zone of the visual mound medial to the lenticular body. It is especially well seen on the frontal cuts of the brain.

The gray matter of the hypothalamus is located around the cavity of the third ventricle of the brain at different depths from its wall and includes more than 32 nuclei. The largest nuclei (Fig. 470) are:
a) the supervising nucleus (nucl. supraopticus), paired, is located lateral to the medial plane above the optic tract from the beginning of the optic tract decussation and extends to the middle of the gray tubercle; the cells of this nucleus produce antidiuretic hormones;
b) the paraventricular nucleus (nucl. paraventricularis), paired, in the form of a plate, is located slightly above the third ventricle. Its lower part begins at the level of the optic chiasm, then goes up and back. The processes of the neurosecretory cells of the oversight and paraventricular nuclei form the hypothalamic-pituitary bundle, which descends along the pituitary stalk to the posterior lobe of the pituitary gland. Receptors of neurosecretory cells are in contact with the blood vessels of the pituitary gland. Neuroserets, penetrating into the blood, excite the cells of its anterior lobe through the portal system of the pituitary gland.
c) the superomedial nucleus (nucl. superomedialis), paired, is located directly behind the paraventricular nucleus, but somewhat deeper;
d) the lower medial nucleus (nucl. inferomedialis), paired, is located somewhat posteriorly and lower than the upper medial. The cells of the superomedial and inferomedial nuclei have adhesive neurons that are in contact with neurons on the opposite side. The functional significance of these two nuclei lies not only in the formation of neurosecrets that affect the adrenal glands. They are intercalary neurons that transmit impulses to the hypothalamus and neurosecretory cells, that is, they transmit impulses to effector neurons that go to the nuclei of the brain stem and spinal cord as part of the medial and posterior longitudinal bundles (fasculi longitudinales medialis et lateralis);
e) the lateral periventricular nucleus (nucl. periventricularis) is located in the wall of the third ventricle at the level and slightly above the infundibulum of the pituitary stalk, behind the lower medial nucleus;
e) the core of the tubercle (nucl. tuberis) is located in front of the base of the funnel. The neurons of the nucleus are sent to the median eminence (eminentia medialis), which is localized in the anterior wall of the pituitary funnel on the border with the gray tubercle. The median eminence is formed by neuroglia, which contains numerous fibers of the infundibulum nucleus, which form axon-vascular contacts in the primary plexus of the pituitary system;
g) the posterior nucleus (nucl. posterior) is large, paired, lies behind the superomedial nucleus, extends to the beginning of the cerebral aqueduct. In this nucleus, as well as in the epithelium and paraventricular nuclei, the body's water-salt metabolism is regulated;
h) the nuclei of the mastoid body (nucl. corporis mammillaris) are located in the mastoid bodies. There are several more small nuclei located in front of and above the medial mastoid nucleus. The nuclei switch impulses from the olfactory analyzer to the nuclei of the thalamus.

Age features of the diencephalon. In newborns, the thalamus is well developed. Its fibers are completely covered with myelin by the 6th month of life. By the time of birth, the nuclei of the hypothalamus are differentiated, the pituitary gland and the pineal gland are well developed.

Hypothalamus, hypothalamus. Gray hillock, tuber cinereum. Mastoid bodies, corpora mamillaria. Posterior hypothalamic region

hypothalamus, hypothalamus, in the broad sense of the word, unites formations located ventrally under the bottom of the third ventricle, in front , including and posterior hypothalamic region, regio hypothalamica posterior.

According to embryonic development, the hypothalamus is divided into two sections: anterior - regio hypothalamica anterior, under whose name they unite tuber cinereum with infundibulum and hypophysis, as well as chiasma opticum with tractus opticus, back - corpora mamillaria and regio hypothalamica posterior.

Nuclei of the hypothalamic region associated with the pituitary gland portal vessels (with anterior pituitary gland) and hypothalamic-pituitary bundle (with its posterior lobe).

Through these connections, the hypothalamus and pituitary gland form a special hypothalamic-pituitary system (HPAS).

A. Tuber cinereum, gray tubercle located in front of corpora mamillaria, represents an unpaired hollow protrusion of the lower wall of the third ventricle, consisting of a thin plate of gray matter. The tip of the tubercle is elongated into a narrow hollow funnel, infundibulum, at the blind end of which is pituitary gland, hypophysis (glandula pituitaria), lying in the deepening of the Turkish saddle (see its description in the section "Organs of internal secretion").

AT Tuber cinereum the nuclei of gray matter are laid, which are the highest vegetative centers, influencing, in particular, metabolism and thermoregulation.

B. Chiasma opticum, optic chiasm, lies ahead gray mound, formed by the optic chiasm, nn. opticali.

AT. Corpora mamillaria, mammillary bodies, - two small white elevations of irregular spherical shape, lying symmetrically on the sides of the midline, in front of substantia perforata posterior. Under the surface layer of white matter inside each of the bodies are two gray nuclei.

According to its function corpora mamillaria belong to the subcortical olfactory centers.

G. Regio hypothalamica posterior, posterior hypothalamic region; This is a small area of ​​the medulla located under the thalamus. It is more lateral substantia nigra lies belonging to the diencephalon oval body, nucleus hypothalamics posterior. It is one of the links in the extrapyramidal system; he is also credited with vegetative functions.