Definition:
A hormone is a chemical substance secreted by a gland or group of endocrine cells that acts to control or regulate a specific physiological process, such as growth, reproduction or metabolism.
Generally hormones are produced in one part of the body and transported via the bloodstream to another part of the body, where they exert their action, although there are some exceptions to this rule.
Some examples of hormones include:
- Insulin
- Testosterone
- Estrogen
- Adrenaline
- Melatonin
- Thyroxine
