3 Regulatory systems of the body and their age features. Age features of the functions of the internal glands.

1. General ideas about the endocrine glands
The endocrine glands are specialized organs that do not have excretory ducts and release secretions into the blood, cerebral fluid, lymph through the intercellular clefts.
Endocrine glands have a complex morphological structure with good blood supply, are located in various parts of the body. A feature of the vessels that feed the glands is their high permeability, which contributes to the easy penetration of hormones into the intercellular spaces, and vice versa. The glands are rich in receptors, innervated by the autonomic nervous system.
A common function for all glands is the production of hormones. Hormones are chemical compounds with high biological activity and in small quantities with a significant physiological effect.
2. Properties of hormones, the mechanism of their action
The action of the hormone on the functions of the body is carried out by two main mechanisms: through the nervous system and humoral, directly on the organs and tissues.
3. Regulation of the activity of the endocrine glands
The leading place in the regulation of the endocrine glands belongs to the central nervous system. There are several mechanisms of regulation:
1) nervous. Direct neural influences play a decisive role in the work of the innervated organs (the adrenal medulla, the hypothalamus and epiphysis neuroendocrine zones);
2) neuroendocrine, associated with the activity of the pituitary and hypothalamus.
3) endocrine (direct influence of some hormones on the biosynthesis and secretion of others (tropic hormones of the anterior pituitary, insulin, somatostatin));
4) neuroendocrine humoral. It is carried out by non-hormonal metabolites that have a regulating effect on the glands (glucose, amino acids, potassium, sodium ions, prostaglandins).

4. Characteristics of individual hormones.