Question

How does the feedback mechanism regulate the hormone secretion?

Answer 1

Hormones are required only when there is a need, so to regulate them there has to be a mechanism to control its secretion, which is called feedback mechanism, which is a turn on and off switch for hormone production.

Complete answer:
Hormones are not necessary to be synthesised continuously all the time but are activated at only specific times. So their secretion or production should be regulated by a certain mechanism. Hormones are required for many cellular functions or metabolism but there has to be some mechanism to control or regulate the hormones also. This is when the feedback mechanism comes into play. The feedback mechanism is a kind of loop wherein the concentrations of hormones are regulated. There are two kinds of feedback mechanism- positive feedback mechanism and negative feedback mechanism, of which negative feedback is more prevalent.

Negative feedback mechanism-
Negative feedback comes into picture when the number of certain hormones becomes too extreme or too high that it needs to be decreased or regulated. The particular hormone feeds back itself to control its amount so that it doesn’t become extreme. A good example of a negative feedback mechanism is of thyroid hormone. The thyrotropin-releasing hormone (TRH) is secreted by the hypothalamus which stimulates the pituitary gland to secrete thyroid-stimulating hormone (TSH). The TSH stimulates the thyroid gland to secrete the thyroid hormones T3, T4, and thyroxine. If the hormonal concentration increases the thyroid hormones signals the hypothalamus and pituitary to inhibit their respective secretion and thyroid hormone is regulated.

Positive feedback mechanism-
In this mechanism, a product increases its amount by a positive feedback mechanism. A very common example of this mechanism is milk production by mammary glands of the female. When a baby suckles the nipple of its mother, it triggers the pituitary gland to produce prolactin hormone, which further stimulates the mammary gland to produce more milk. The production of milk increases more and more as the baby suckles as the amount of prolactin is also increased.

Note: Hormones are biological substances, which helps to regulate the functions of the body. It mainly plays a key role in maintaining proper homeostasis and metabolism of our body. Hormones are always required in optimal concentration. Deficiency or excess of any hormones leads to many disorders of the living system. The feedback loops act as a switch, which turns on and off to maintain proper levels of it in our body. If a certain hormone is more feedback loop acts to reduce its quantity and when hormone secretion is less feedback aids in increased release to compensate.