Hormone: chemincal signal that is secreted into body fluids, mostly blood, and communicates
messages within body
Target cells: cells that respond to particular hormone.
Endocrine Glands: galnd that secretes hormones into body fluids. (opposite of exocrine gland)
Neurosecretory cells: Specialized cells that produce hormone and are signal to do so by neurons.
Hormones: over 50 known hormones in the body; specific protein shape that targets specific
receptors on target cells.
3 Major groups
-Steroids: 4 ring strkucture; derived from cholesterol
