Certain glands exert enormous influence over the way we feel and the way we physically react. They exhibit this power through their control over that intriguing and not yet fully explored province of the body, its chemistry.
The endocrines are the great chemical regulators of bodily function. The substances which are secreted by the endocrines, and which serve as chemical messengers are called hormones, from the Greek hormon meaning arouse to activity. Another version of the word means vital principle which, the Greek believed, was contained in certain body secretions and generally enlivened the body.
Along with the nervous system, the endocrine system serves as the major means of controlling the body’s activities. The nervous system is built for speed; it enables the body to adjust its internal processes rapidly, as changes take place in the environment. The endocrine, on the other hand, regulate continuing process of longer duration including the body’s growth, sexual maturation and ability to reproduce. The pituitary at the base of the brain; the thyroid gland in the neck, the adrenals, a perched atop the kidney like miniature peaked caps; the insulin-making islets of Langerhans in the pancreas; the ovaries in the abdomen of the female; the testicles in the scrotum of the male. The placenta, which feeds the unborn child, also behaves like an endocrine, manufacturing special chemicals essentials to successful pregnancy.
Endocrines are bits of tissue tucked away in obscure corners of the body. But in the widespread control they exercise over the body, they are little giants.
All hormones regulate one or more chemical reactions in the body, but they seem to work in many different ways. Hormonal activity must remain in delicate balance or the entire body will be thrown out of balance.
Endocrinology is the study of endocrine systems. The primary function of endocrine system is to regulate physiological processes by means of groups of chemical messengers called hormones. These substances are released by an endocrine organ into the blood in which it travels to another site in the body where it exerts its effect.