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Diagnosis of the endocrine system
Last reviewed: 18.10.2021
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The endocrine system includes endocrine glands that secrete the corresponding hormones into the blood. These glands include the pituitary gland, the thyroid gland, the parathyroid glands, the islet apparatus of the pancreas, the adrenal glands, including the cortical and medulla, the testes, the ovaries, the epiphyses, the thymus gland (thymus). The endocrine system is functionally closely related to the nervous system. Their interaction is largely due to the hypothalamus, which produces hormones that enhance or depress the activity of the anterior pituitary cells, secreting in turn the so-called tropic hormones that affect the function of these endocrine glands.
To date, it has been established that, in addition to endocrine glands, a number of other organs also have cells that secrete hormonal active substances. Thus, the cells of the juxtaglomerular kidney apparatus secrete renin, which participates in the formation of angiotensin. In the kidneys formed erythropoietin, which stimulates erythropoiesis. In the central nervous system, neuroendocrine peptides - endorphins and others are formed. In the atria, a natriuretic peptide is formed, which contributes to the release of sodium and water by the kidneys. In the gastrointestinal tract there are accumulations of cells belonging to the so-called APUD-system (APUD) and forming polypeptide hormones affecting the function of the digestive system. Thymus gland (thymus) produces hormonal-active substances involved in the differentiation of T-lymphocytes and the functioning of the immune system. Close to hormones in its importance and role in the body prostaglandins, thromboxane and prostacyclin, a number of other substances.
Most of the hormones secreted by the endocrine glands circulate in conjunction with blood proteins (eg, glucocorticosteroids, thyroid hormones) and exert their effect by binding to cellular receptors in target tissues.
Regulation of hormone secretion is based on the feedback system: if the hormone release leads to a change in the function of the target organ and, as a result, the internal environment of the organism changes, then substances that inhibit the release of the hormone begin to be produced. Particular participation in this regulation takes the system hypothalamus - pituitary: tropic hormones of the pituitary gland stimulate the function of other endocrine glands, hormones secreted by these glands, suppress the secretion of hormones in the hypothalamus and the pituitary gland. This regulatory system acts in a certain rhythm, which should be taken into account when assessing, for example, their blood content. The variety of biologically active substances with different effects, peculiarities of their formation regulation make the clinical manifestations of these effects extremely diverse, although many of them are quite typical for the states of increased and reduced production of hormone-active substances.
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