22 terms

General Characteristics of the Endocrine System

The endocrine system functions with the nervous system in....
communication and control of the body
Main function
to maintain homeostasis
Cells, tissues, and organs of the endocrine system
ductless; secrete hormones,
paracrine glands
affect only neighboring cells
autocrine glands
leave gland but only affect cell that secreted it
exocrine glands
have ducts; deliver their product directly to a specific site
release neurotransmitters
endocrine glands
release hormones
hormones are released...
into the extracellular space surrounding endocrine cells
a chemical messenger, steorid or non-steroid based
hormones play a key role...
in maintaining homeostasis; the can activate or inactive genes
paracrine substances that are potent in small amounts and are synthesized just before release before rapidly inactivating
prostaglandins functions
regulate blood pressure, contract smooth muscles in walls of uterus (menstrual crams/ labor contractions), inhibit secretion on hydrochloric acid from wall of stomach
Prostagladins can activate or inhibit ___ which ___
adenylate cyclase; controls cAMP production or alters a cell's response to a hormone
hormonal secretions are....
primarily controlled by negative feedback
time it takes for half a molecule to break down
short half-life
hormone is quick acting
long half-life
hormone is slow acting
trophic hormones
help stimulate other glands to produce hormones
Pituitary gland
lies at the base of the brain in the sella turcica; consists of anterior and posterior portions
Anterior Pituitary gland
carry out most secretions, rich capillary bed, enclosed in a capsule that houses specialized epithelial cells
Posterior Pituitary gland
structurally consists of nerve fibers and neuroglia epithelial cells of the anterior pituitary gland; nerve fibers originate in the hypothalamus