HORMONES – organic compounds produced by certain cells and designed to control the functions of the body, their regulation and coordination.
Higher animals have two regulatory systems, through which the body adapts to constant internal and external changes. One of them is the nervous system, which quickly transmits signals (in the form of impulses) through the network of nerves and nerve cells; The other is the endocrine system that performs chemical regulation with the help of hormones that are carried by the blood. They are in all mammals, including man. Plant hormones and insect moult are well described.
As a medical discipline, endocrinology appeared only in the 20th century, but observations have been known since antiquity. Hippocrates believed that human health and his temperament depend on special humoral substances. Aristotle drew attention to the fact that a castrated calf, growing up, differs in sexual behavior from a castrated bull by not even trying to climb a cow. In addition, for centuries castration has been practiced both for domestication and domestication of animals, and for the transformation of man into a submissive slave.
WHAT ARE HORMONES
According to the classical definition, hormones are secretion products of the endocrine glands, which are released directly into the bloodstream and possess high physiological activity. The main endocrine glands of mammals are the pituitary gland, thyroid and parathyroid glands, the adrenal cortex, adrenal medulla, pancreatic islet tissue, genital glands (testes and ovaries), placenta and hormone-producing sites of the gastrointestinal tract.
In the body, some compounds of hormone-like action are synthesized. For example, studies of the hypothalamus have shown that a number of substances secreted by it are necessary for the release of pituitary hormones. These “releasing factors,” or liberins, were isolated from various parts of the hypothalamus. They enter the pituitary gland through a system of blood vessels that connect both structures. Since the hypothalamus is not a gland in its structure, and the releasing factors appear to come only to a very closely located pituitary gland, these substances released by the hypothalamus can be considered hormones only in the broad sense of the term.
In determining what substances should be considered hormones and which structures are endocrine glands, there are other problems. It is convincingly shown that organs such as the liver can extract from the circulating blood physiologically inactive or completely inactive hormonal substances and convert them into potent hormones. For example, dehydroepiandrosterone sulfate, a low-active substance produced by the adrenal glands, is converted in the liver into testosterone, a highly active male sex hormone secreted in large numbers by the testes. Does this prove, however, that the liver is an endocrine organ?
Other issues are even more difficult. The kidneys secret the enzyme renin into the bloodstream, which through the activation of the angiotensin system (this system causes the expansion of blood vessels) stimulates the production of the adrenal hormone aldosterone. The regulation of the release of aldosterone by this system is very similar to how the hypothalamus stimulates the release of the pituitary hormone ACTH (adrenocorticotropic hormone, or corticotropin) regulating the function of the adrenal glands. The kidneys also secrete erythropoietin, a hormonal substance that stimulates the production of erythrocytes. Can I carry the kidney to the endocrine organs? All these examples prove that the classical definition of hormones and endocrine glands is not sufficiently exhaustive.
ACTION OF HORMONES
Physiological action is directed to:
1) ensuring the regulation of biological processes;
2) maintaining the consistency of the internal environment;
3) regulation of the processes of growth, maturation and reproduction.
Hormones regulate the activity of all cells in the body. They affect the acuity of thinking and physical mobility, physique and growth, determine hair growth, voice tone, sex drive and behavior. Thanks to the endocrine system, a person can adapt to strong temperature fluctuations, surplus or lack of food, to physical and emotional stress. The study of the physiological action of the endocrine glands and hormones made it possible to reveal the secrets of sexual function and the miracle of the birth of children, and also to answer the question why some people are tall and others are low, some full, some thin, some sluggish, others agile, some strong, others weak .
In a normal state, there is a harmonious balance between the activity of the endocrine glands, the state of the nervous system and the response of target tissues (tissues targeted by hormones). Any violation in each of these links quickly leads to abnormalities. Excess or inadequate production of them causes various diseases, accompanied by deep chemical changes in the body.
WHY ARE HORMONAL DISTURBANCES
Disorders of the function of hormones in the body can be caused by the following reasons:
- Insufficient hormone. Occurs with a decrease in the production of hormones by the endocrine gland for various reasons: infections, heart attacks, autoimmune processes, tumors, hereditary diseases.
- Excess of the hormone. Occurs with excess production and release into the bloodstream of hormones. The reasons for this may be excessive synthesis of hormones by the endocrine gland, the production of hormones by other tissues (usually with malignant regeneration), the increase in the production of hormones from tissues from its predecessor and iatrogenic causes when excess hormone is introduced when hormones are prescribed as a medicine.
- Synthesis of abnormal hormones by endocrine glands. More often it occurs with congenital genetic abnormalities.
- Resistance to hormones. In this case, the body tissues do not give a normal reaction to a normal or increased amount of the hormone in the blood. Resistance (insensitivity) of tissues to the hormone has various causes: hereditary nature, a defect of tissue receptors, the appearance of antibodies to hormones.
WHAT HORMONES SHOOT BLOOD?
What tests for hormones you need to take depends on your health and disease, determined by your doctor. They can surrender several times, which allows you to evaluate the effectiveness of treatment or changes in health status. Here you can see in more detail what kind of …