18.1-18.5 Flashcards
Hormone
Mediator that is released in one location of the body but regulates in another location.
Hormon-to excite or get moving
2 types of glands:
Endocrine and exocrine
Exocrine
Secrete into ducts that carry into body cavities, organs, and outside the body
Endocrine
Secrete hormones into interstitial fluid surrounding the secretory cells rather than into ducts.
What glands are part of the Endocrine Glands?
5 specific glands:
Pituitary, thyroid, parathyroid, adrenal, and pineal.
Organs that contain cells that excrete hormones (endocrine):
Hypothalamus, thymus, pancreas, ovaries, testes, kidney, stomach, liver, small intestine, skin, heart, adipose tissue, and placenta.
Endocrinology
Science of the structure and function, and diagnosis and treatment, of endocrine glands
Down-regulation
When the target-cell receptors decrease in number, if a hormone is present in excess.
(Makes a target cell less sensitive to a hormone)
Up-regulation
When a hormone is deficient, receptors increase, making a target cell more sensitive to a hormone.
Circulating hormones
Pass from the secretory cell into interstitial fluid and then the blood
Local hormones
Act locally on the same or nearby cell that secreted them without entering bloodstream.
Local hormones that act on neighboring cells
Paracrines
Local hormones that act upon the same cell that secreted them are called
Autocrines
Auto means self
2 chemical classes of hormones are
Lipid-soluble hormones
Water-soluble hormones
3 types of lipid soluble hormones:
(1) steroid hormones
(2) thyroid hormones
(3) nitric oxide