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The human endocrine glands


The human species, like other vertebrates, has several endocrine glands, some of which are responsible for producing more than one type of hormone.

THE pituitary or pituitary gland It has long been considered the master gland of the endocrine system for controlling the activity of other organs, whether glandular or not. It is known today that even it is under the control of the hypothalamus, a structure belonging to the central nervous system, to which the pituitary is attached.

This control is exerted by the so-called hypothalamic release factors (stimulants or inhibitors), which regulate the synthesis of pituitary hormones. In the region of union between hypothalamus and pituitary, a rich network of blood vessels favors the arrival of hypothalamic release factors to the pituitary cells. Hence, the various hormones produced by the pituitary gland fall into the bloodstream and are routed to different sites of action.

The pituitary

Pea-sized and located at the base of the brain, the pituitary has an anterior portion (also known as the adenoipophysis) and a posterior portion (neuroipophysis), among which is a middle portion, poorly developed in humans.

The hormones of adenoipophysis are collectively known as trophies (from the Greek, trophé = nutrition), so called because they work by stimulating the activity of other organs or glands. The hormones of the posterior portion are actually produced by the hypothalamus.

See table on pituitary hormones

Hormones Acting

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Growth - GH (Somatotropin)

It acts on the growth of various tissues and organs, particularly bones, as a result of stimulation of protein synthesis (it is therefore considered an anabolic hormone). In childhood, its deficiency leads to a picture of pituitary dwarfism, causing short stature, and its excess leads to a picture of gigantism, characterized by overgrowth of the whole organism. Excess in adults causes enlarged extremities (hands, feet, jaws), known as acromegaly. Nowadays, using genetic engineering techniques, it is also synthesized by bacteria.

Adrenocorticotrophic - ACTH

It acts in the cortical region of the adrenal (adrenal) gland, stimulating it to produce the hormones cortisol and aldosterone.

Prolactin - PRL

It works by stimulating milk production by the mammary glands during lactation.

Stimulating Follicle - FSH (Gonadotropin)

It acts on the ovaries, stimulating the development of ovarian follicles, within which egg maturation occurs. In humans, it stimulates sperm formation.

Luteinizing - LH (Gonadotropin)

It acts on the rupture of the ovarian follicles, which results in the release of the egg. After rupture, the follicle becomes the corpus luteum (yellow body). In men, it acts on the testicles, stimulating the synthesis of testosterone (male sex hormone).

Thyroid Stimulant - TSH (Thyrotropin)

It acts by stimulating the synthesis of thyroid hormones, which will act in the regulation of cellular metabolism.

P M
The is
R D
I
à A
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Melanotrophic - MSH

Related to skin coloration in amphibians and reptiles, especially during camouflage or bridal cuts. In man there is no known function.

P P
O O
LOL
Ç T
Yeah
O R
I
O
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Oxytocin - OT and Antidiuretic - ADH or HAD

The posterior portion releases two hormones that are actually produced by the hypothalamus: oxytocin and the antidiuretic hormone. The first stimulates uterine contraction during labor and the contraction of the smooth muscles of the mammary glands in the expulsion of milk. The second, which stands for ADH (or HAD), acts on the renal tubules, promoting water reabsorption.