Source: Endocrine System image, Public Domain: http://en.wikipedia.org/wiki/File:Endocrine_central_nervous_en.svg; Alimentary image, Public Domain: http://en.wikipedia.org/wiki/File:Endocrine_Alimentary_system_en.svg
A system of glands that produces and secretes hormones into the bloodstream; the endocrine system is used to communicate on a broad scale to the cells in the body.
The major chemical messenger of the endocrine system, hormones are produced, stored and secreted by glands; hormones either increase or decrease activity of the cells with which they interact.
A term used to describe hormones that create opposite effects of one another; an example would be insulin lowers blood glucose while glucagon elevates blood glucose.
A term used to describe hormones that create similar effects through slightly different mechanisms; an example would be ADH stimulating kidneys to retain water while aldosterone stimulates kidneys to retain sodium, which in turn retains water.
When one hormone allows another hormone to have its full effect; an example would be thyroid hormones allowing growth hormone to have its full metabolic effects.
The cell or group of cells with which a hormone is designed to interact.