What glands belong to the glands of internal secretion? Functions of endocrine glands

The work of all organs and systems is coordinated by a number of certain internal factors. Thanks to their well-coordinated mechanism, the human body reacts correctly and in time to the action of stimuli. The endocrine system belongs to one of the main roles in these processes.

The basis of this system are intrasecretory glands. What should be attributed to the glands of internal secretion, whether they refer to the glands of the brain and what features of their work can be distinguished - consider below.

Endocrine system and its features

The endocrine apparatus is represented by working cells, some of which are localized, forming an organ, while others are in a free scattered state. The organs that belong to this system are called the glands of internal secretion. The peculiarity of their anatomy lies in the fact that the outflow ducts, through which the produced secretion occurs, open into the body.

Its endocrine system performs its regulatory function through the production of specific substances - hormones. These chemicals are important functional mechanisms necessary for the adequate functioning of the body as a whole.

Functions of endocrine glands

After getting hormones into the circulatory, lymphatic system or cerebrospinal fluid, they begin to act as catalysts. The main functions of endocrine glands are based on the following processes:

• Participation in the metabolism;
• Coordination of the work of the organism and interaction of all its systems;
• Preservation of equilibrium under the influence of external stimuli;
• Regulation of growth processes;
• Control of sexual differentiation;
• Participation in emotional and mental activity.

The active substances produced by the system of endocrine glands are specific factors, since each of them also performs a certain function. Hormones act in the human body in the presence of the necessary physical and chemical conditions. This happens depending on the constituent elements of food that enters the body, and the intermediate stages of metabolism.

Hormones have the property to influence the work of organs and glands remotely, that is, being away from the target. Another feature is that the change in the temperature regime does not affect the operation of the active substances.

The glands of the endocrine system

The glands of internal secretion include the pituitary gland, parathyroid and thyroid gland, pancreas, adrenal glands, ovaries and testes, the epiphysis.

The thyroid, the adrenal cortex and the sex glands are considered dependent in their work from the pituitary gland, because the pituitary hormones directly affect the glands.

The remaining glands are not tropic, that is, they do not obey the work of the pituitary system.

All glands of internal secretion are represented here. The table also indicates the localization of the organs and the hormones that they produce.

Glands of the brain

The glands of internal secretion include the pituitary gland and the epiphysis. Let's consider the work of each of them in more detail.

The pituitary gland is located in the Turkish saddle of the brain, in front it is protected by the saddle bones of the skull. This gland is considered the beginning of all metabolic processes occurring in the body. It consists of two parts, each of which produces specific active substances:

• Anterior - adenohypophysis;
• Posterior - neurohypophysis.

Both lobes are autonomous from each other, since they have a separate innervation, circulation and communication with other parts of the brain.

One of the parts of the pituitary gland constantly produces an antidiuretic hormone, or vasopressin. The function of this substance is very important for a person, since it controls the fluid balance and the functioning of the renal tubules. When the antidiuretic hormone enters the bloodstream, the kidneys begin to trap water in the body, and with a decrease in its amount - to give up its external environment.

Oxytocin is a "female" hormone, although it is present in the body of men. His work is manifested in the ability of the muscles of the uterus to actively reduce, that is, the substance is responsible for adequate generic activities. This same hormone is involved in the processes of removal of the afterbirth in the postpartum period and lactation after childbirth.

Adenohypophysis deals with the coordination of the work of some endocrine glands. What glands of internal secretion are regulated by the anterior lobe of the pituitary system and by what substances does it occur?

1. Thyroid gland - its work is directly dependent on the thyroid-stimulating hormone.
2. Adrenal glands are regulated by the level of adrenocorticotropic hormone in the blood.
3. Gonads - their work is affected by FSH and LH.
4. Prolactinum is an adenohypophysis hormone that affects the work of the mammary glands during lactation. Somatotropin - a substance whose task is to coordinate the growth of the body and its development, as well as participation in protein biosynthesis.
5. Hormones of the pineal gland are involved in the regulation of daily biorhythms, stimulate the immune system, reduce stress and blood pressure, and reduce sugar levels.

Thyroid and parathyroid glands

The glands of internal secretion are thyroid and parathyroid. They are located in one area - at the level of the middle cartilages of the trachea.

Hormones of the thyroid gland are considered iodine-active active substances - triiodothyronine, thyroxine. They take part in metabolic processes, regulate the level of absorption by the cells of the body of glucose and break down fats. Thyreocalcitonin lowers the level of calcium in the blood.

The main function of the parathyroid gland and its hormone is based on improving the work of the nervous and musculoskeletal system, which is achieved by increasing the level of calcium in the body and its absorption by cells.

Functional features of the pancreas

This body applies not only to the endocrine system, but also to the digestive system. Hormonal function is performed by the so-called islets of Langerhans, which are located in the tail of the gland. These islands have in their composition several types of cells, differing in structure and hormone, which they produce:

• Alpha cells: produce the hormone glucagon (regulates the metabolism of carbohydrates);
• Beta cells: produce insulin (reduces the amount of sugar in the blood);
• Delta cells: somatostatin secretion;
• Epsilon cells: produce a "hungry" ghrelin hormone.

Adrenal glands and their hormones

The gland is represented by the outer layer of cells (cortical part) and internal (the brain part). Each of the parts produces its own specific active substances. The cortical layer is characterized by the production of glucocorticoids and mineralocorticoids. These hormones take an active part in metabolic processes.

Adrenaline is the hormone of the internal substance responsible for the work of the nervous system. With a sharp increase in its quantity in the bloodstream, there is tachycardia, hypertension, pupil dilatation, and muscle contraction. Norepinephrine is also synthesized by the inner layer of adrenal cells. Its action is aimed at activating the work of the parasympathetic nervous system.

Gonads

The glands of internal secretion also include testes and ovaries. The hormones they produce are responsible for the normal functioning of the reproductive system. For women, this is the period of maturation, pregnancy and labor. Male hormones are also responsible for the maturation and appearance of sexual characteristics.

Functions of endocrine glands are based on direct and feedback. Testes and ovaries belong to the group of tropic organs, since their work directly depends on the adenohypophysis.

The most common misconceptions about the endocrine system

Many people mistakenly believe that all glands in the human body can be called incretory.

If you ask the following question: "Do the glands of internal secretion include the mammary glands?", Then there will be an unambiguous answer - no. Mammary glands belong to the group of excretory organs, that is, their outflow ducts open outward, and not inside the body. In addition, the mammary glands do not produce hormones on their own.

The negative answer will be to this question: "Do glands of internal secretion include lacrimal glands?" From the point of view of medicine, lacrimal glands, as well as dairy glands, do not belong to the organs of the endocrine apparatus, since they do not have the ability to produce hormone-active substances.