endocrine Flashcards
(139 cards)
Function of endocrine glands
Lack ducts and release hormones into the blood or surrounding tissues. Since hormones travel in the extracellular fluid, they can act on cells that are quite a distance away from the original secreting endocrine gland
major endocrine organs and structures
pineal gland, hypothalamus, pituitary gland, thyroid gland, parathyroid glands, thymus, adrenal glands, pancreas, gonads,
what are the 2 basic categories of hormones?
water soluble (hydrophilic) and lipid soluble (hydrophobic)
water soluble hormones or hydrophilic tend to be
amino acids based water soluble proteins.
lipid soluble hormones are usually
steroids and derived from cholesterol
what are the category of structures that are fatty acids that don’t fit the typical description of a hormone. they don’t travel in blood they function more locally
prostaglandins
Our two categories of hormones act differently
True
When a hormone binds to a cell it alters the cell’s activityA hormone may increase or decrease a particular cell’s activity and the affect a given hormone has on a cell is specific to the cell, not the hormone. This is called
target cell
Hormones have 2 basic mechanisms of action depending on whether they are
water or lipid soluble
things that move readily across the cell membrane are
lipid soluble
the things that do not move easily over the cell membrane
water soluble molecules
Something that is polar,____ ______ go across the phospholipid by layer.
does not
for water soluble cells the receptors are on the _____ of the cell
outside
water soluble hormones start a cascade effect once they bind to their receptors this is called _________
second messenger system or cyclic AMP - two atp
The first horomone that bonds to water soluble cell is called
first messenger
The hormone is called the first messenger and its binding to a receptor causes the activation of a
G protein
The activated G protein actives the enzyme, adenylate cyclase, which takes ATP and forms cAMP, cyclic AMP. cAMP, this is called the
second messenger
the second messenger, then floats in the cell and activates another enzyme,
protein kinase
Protein kinases are a group of enzymes that add a phosphate group to another
protein
The second messenger system is an example of a
cascade effect
what is cAMP
Cyclic AMP - Intracellular second messenger that mediates the effects of the first (extracellular) messenger (hormone or neurotransmitter); formed from ATP by a plasma membrane enzyme (adenylate cyclase).
Cyclic AMP is the
most common 2nd messenger in the body
Once the hormone get attached to the receptor the reaction is very
FAST
all hydrophyllic hormones work
FAST