Thyroid hormones: source, meaning, pathology

The human body is a well-coordinated system in which all processes are regulated among themselves. And each body in its composition contributes to the maintenance of holistic work.

Along with the brain, one of the most important mechanisms of regulation is the human endocrine system. It carries out its action through endocrine glands that secret hormones that have certain functions and tropism to specific target cells. So, the thyroid gland plays an important role in the development of the body, affects all types of metabolism. It secretes thyroid hormones, which promote physical and mental development in children, provide metabolism and energy in adults. In turn, their production is regulated by the nervous system, namely the biologically active substances of the pituitary gland and the releasing factors of the hypothalamus. Thus, thyroid hormones are always at a certain level in the blood and rise with special needs of the body, their lowering may indicate a deficiency of thyroid or iodine function.

Hormones

Glandula thyroidea (thyroid gland) is attached to the trachea and consists of the right and left lobes connected by an isthmus. Direct synthesis of thyroid hormones is carried out in its follicles, filled from the inside by a colloid, the basis of which is protein - thyroglobulin. With further iodination of amino acid residues of tyrosine in its structure and subsequent summation of the resulting compounds, triiodothyronine and tetraiodothyronine (T3 and T4) are formed. Further, the resulting thyroid hormones are cleaved from the thyroglobulin molecule and enter the bloodstream in a free form. They have different concentrations, and also differ in the strength of the action (T3 is released significantly in smaller doses, but the force of its action is much greater than in T4). However, the effect on the body hormones are the same: they increase fat and carbohydrate metabolism (increase the level of glucose), trigger gluconeogenesis, in the liver inhibit the formation of glycogen and increase the synthesis of protein (in excess, on the contrary, increase the breakdown of the latter).

Outwardly this is manifested by the fact that they maintain blood pressure and heart rate, as well as body temperature, accelerate the mental and emotional processes. In the embryonic period, thyroid hormones are responsible for differentiating the tissues of the whole organism. In childhood, they contribute to the growth and mental development of the child. In addition, they increase erythropoiesis, lower the tubular water reabsorption.

Diseases

With some diseases of the thyroid gland, the release of hormones decreases (hypothyroidism). In this case, they need to be replaced with medicines. What can compensate for the lack of content of such elements as thyroid hormones? The drugs used in this case are "Levothyroxine" (T4), "Lytryronin" (T3) and various iodine-containing medications. Both a deficiency and an excess of thyroid hormones lead to metabolic diseases in the body, which are clinically manifested by a violation of homeostasis and psychomotor activity. The degree of lesions depends on the age of the patient (cretinism only in children), the level of deficiency or excess of hormones (hyperthyroidism 1, 2, 3 degrees). At the latter, shortness of breath, palpitations, increased blood pressure, violation of all types of metabolism. With a lack, on the contrary, the metabolism is reduced, the patient becomes listless, indifferent.