How Do You Define A Hormone?

A hormone is a chemical matter produced in the body that manages and regulates the movement of certain cells or organs. It is manufactured by a particular tissue and transmitted by the blood stream to another, to cause physiological activity like metabolism or growth. Most of the hormones are secreted by specialised glands like the thyroid gland. Hormones are vital for every process which is carried in our body be it digestion, growth, metabolism, stress control, mood swings, reproduction, menstruation etc.

The word hormone comes from the Greek word "hormao" which means to "put in motion or "stir up". The word "hormao" was rechristened as "hormone" in the year 1902 by the English physiologists Bayliss and Starling who discovered a substance produced by glands in the small intestine which could stimulate pancreatic secretion. They called the substance "secretin". This was the first hormone known to man. Examples of other hormones are aldosterone, cortisol, estrogen, progesterone, testosterone, antidiuretic hormone (ADH) etc. In today's parlance, a hormone has a broader significance. It can be any chemical irrespective of whether it is manufactured by a particular gland or not, for export or domestic usage as long as it regulates and manages the movement of cells or organs.