Book

• Endocrine system is composed of endocrine glands
• hormones- chemical messengers that are produced by glands and travel through the bloodstream
• hormones circulate through bloodstream to specific site called target tissues
• endo- within
• krino- to secrete
• exocrine glands have ducts that carry their secretion to the outside of the body
• Saliva, sweat, breast milk, and digestive system is example of exocrine gland
• endocrinology- study of endocrine system
• Chemical messengers - allow cells to communicate with each other and with the environment.
• Secretion- controlled release of chemicals from a cell
• Autocrine- secreted by cells in a local area, stimulates the cell to produce more of itself
• Paracrine- produce tissues and secreted into extracellular fluid
• neurotransmitter- chemical messenger that is released from a neuron and diffuses across the synapse
• endocrine- secreted into the blood by specialized cell
• endocrine- hormones are released into the bloodstream and travel to target tissues
• lipid-soluble - nonpolar, include steroid hormones, thyroid hormones and fatty acid
• binding proteins- the chaperone the hormone
• water-soluble hormones - polar molecules, and include protein, peptide, and most amino acid derivative
• Water-soluble are more stable in the blood than the others