Chapter 17 part 2 Endocrine System Organization Flashcards
what prevents hormones from being broken down by hydrolytic enzymes after entering the bloodstream?
binding proteins
what act as chaperones that protect hormone and remain intact/functional at target site?
binding proteins
what is a hormone attached to a binding protein called?
bound hormone
Hormones bind to _____ binding proteins
specific
testosterone binds to…
testosterone binding globulin
progesterone binds to…
progesterone binding globulin
Why is binding proteins a reversible action?
they detatch at target tissues
when binding proteins detach from hormones the hormones are called…
free hormones
hormones that do not have any specific binding proteins are…
ALWAYS free
what kind of hormones can diffuse through capillary walls and bind target tissues?
free hormones
Why can’t bound hormones diffuse?
TOO BIG
bound hormones can act as a _______ is hormone levels decrease
reservoir
(they release them to get levels up)
What are the 2 hormone classes?
lipid soluble, water soluble
What kind of hormones cant pass through cell membrane, but travel easy in the blood?
Water soluble
Examples of water soluble hormones
(6)
LH
TSH
ADH
PTH
Insulin
EPI
What hormones easily cross cell membranes?
Lipid soluble
Examples of lipid soluble hormones?
steroids (testosterone, estrogen)
THYROID HORMONES
What are the two receptor classes?
Nuclear and membrane bound receptors
what receptor is bound by lipid soluble hormones?
nuclear
What receptor is bound by water soluble hormones?
Membrane bound receptors
lipid soluble hormones are _____ and ______
small and nonpolar
Where are the two places nuclear receptors are found?
usually the nucleus, sometimes cytoplasm(move to nuc once activated)
What is the result after binding to nuclear receptors?
modify gene expression/ transcription AND stimulate new protein synthesis
Nuclear receptors have what kind of effect on target cells?
rapid