Glands of mixed secretion (Pancreas. Sex glands)
Mixed secretion glands
Glands of mixed secretion are glands, some cells of which produce hormones, while others secrete secretions that enter organs or the external environment through special ducts.
The glands of mixed secretion include: part of the pancreas, gonads (testes in men and ovaries in women) and some other glands.
The pancreas is located next to the duodenum, behind the stomach.
The pancreas is a mixed secretion gland. It contains groups of cells that secrete pancreatic juice into a duct that opens into the duodenum. This is an external secretion. Other groups of cells produce hormones that enter the bloodstream. This is internal secretion.
Pancreatic hormones control blood glucose levels:
- insulin ensures the transfer of glucose from the blood to the tissues and the transformation of its excess into glycogen, which is deposited in the liver; the level of glucose in the blood decreases at the same time;
- glucagon, on the other hand, converts glycogen to glucose and increases its level in the blood.
With a decrease in the production of insulin, the sugar content in the blood increases, and a disease occurs – diabetes mellitus. Patients with diabetes mellitus feel constant thirst, lose weight quickly.
The excretion of glucose from the body along with urine indicates a failure of the pancreas function and possible diabetes mellitus.
The sex glands of men are the testes, women are the ovaries.
In the gonads, not only sex hormones are formed, but also sex cells (eggs, sperm), therefore they belong to the glands of mixed secretion.
The development of the gonads is associated with the general development of the human body. In childhood, these glands do not develop (they are in a “dormant state”). At the age of 12–16 years, the process of sexual development begins (puberty, or puberty), as a result of which puberty begins (the sex glands begin to produce sex hormones, and germ cells also begin to mature in them).
Male sex glands
The testes secrete sperm cells into the external environment (external secretion), and into the internal environment – hormones androgens, the main of which is testosterone (internal secretion).
Testosterone determines the development of male genital organs and secondary sexual characteristics (muscle formation, body hair distribution, voice timbre, behavioral features, etc.). This hormone also controls sperm maturation.
Female sex glands
In the ovaries, eggs are formed (exocrine function), and the female sex hormones estrogens and progestins (intrasecretory function).
Estradiol determines the development of secondary sexual characteristics in women (the formation of mammary glands, body type, high-pitched voice, etc.). This hormone also controls the menstrual cycle.
Progesterone, or “pregnancy hormone”, is produced in the body of pregnant women. It stops the maturation of new eggs, temporarily stops menstruation and controls the progress of pregnancy.
Normally, a certain amount of female hormones is produced in the testes, and male hormones in the ovaries. If the ratio of sex hormones in the body is violated, then intersexuality occurs. Men show some feminine characteristics, while women show some masculine ones.