Endocrine Glands

Endocrine Glands

Hormones are chemical substance which are required in minute quantity for the normal functioning of the body. Both plants and animals secrete hormones of different kinds to control different physiological body functions. In the absence of particular hormones some disorder take place in body functions.

Hormones were first designated as ‘Secretin’ by Bayliss and Starling (1902) and the word hormones was first used by Starling (1906) for certain chemical substances secreted by animals. In animals these chemical substance are secreted by endocrine glands and carried by blood to different parts of the body where they control and regulate the normal physiological functions of the body. The word ‘endocrine’ is a Greek word which means internal secretion Endocrine glands have no ducts, so they are also called ductless glands. As hormones are secreted within the body they are called internal secretions. Hormones are chemical substances and control the body functions so they are called chemical messengers or chemical co-ordinators. Some hormones are made of steroids, some are made of amino acids or proteins. Many of them have been synthesized in the laboratory.