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
What binds to DNA to stimulate protein synthesis?
hormone receptor complex
(example testosterone –> protein synth —> secondary sex characteristics)
water soluble hormones are _____
LARGE
What are the 3 types of membrane bound receptor complexes?
- ligand gated ion channels
- G protein coupled receptors
- Enzymatic receptors
what receptor is bound by neurotransmitters to open gate (NA, K, CL, CA2 flow thorugh)
ligand gated ion channels
what is the most common receptor pathway?
G coupled protein receptor
what is the secondary messenger of GCPR?
cAMP
what receptors are linked to enzymes in target cells?
enzymatic receptors
what are the 2 examaples of enzymatic receptors
guanylate cyclase receptor
receptor tyrosine kinase
hormone concentrations are _____ in the bloodstream
stable
the larger more complex the hormone =
the more stable
what determines hormone lifespan?
chemical composition
What is the amount of time it takes for 50% of circulating hormone to be removed from circulation and be excreted (variable timeframe)
half-life
What hormone is 3 AA, simple, short half life, quick degredation?
TRH
What hormone is a steroid with long half-life? (hint: adrenal glands)
cortisol
all hormones will eventually..
be destroyed in circulation or by enzymes at target cells
What limits the time of activity?
destruction
water soluble hormones typically have ____
shorter half lives
What breaks down water soluble hormones in the blood?
hydrolytic enzymes (proteases)
hormones with short half life have concentrations that change alot in the blood so they tend to regulate activities with _____ and ______
rapid onset and short duration
What are the 3 ways to avoid hormone destruction (or delay it ?)
- have carbohydrate attach
- have a modified terminal end (protects from protease)
- have binding proteins
what are hormones with a carbohydrate called?
glycoproteins
hormones specifically bind to receptor at the _____ ______
binding site
How are hormone receptors specific?
designed so only 1 hormone can bind to it
some hormones can bind to a ______ of receptors with similar structures and different effects
Family
Hormones can have different ____ on different __________
effects
target areas
What hormone binds to a family of receptors?
Epi
Epi can stimulate smooth muscle _____ and ______ simultaneously in the blood vessels and bronchioles
contraction and relaxation
receptors have high ______ for hormones that bind them
binding affinity
do you need a large hormone concentration to activate a lot of receptors?
no! binding affinity makes the receptors extra sensitive
To optimize target tissue response you need to….
increase # of receptors
= enhance sensitivity = more chance for effect
target tissue response becomes desensitized when _____ occurs
down regulation
What decreases that makes cells unable to responde to hormone? (2)
nutrients and energy
What is it called when # of receptors quickly drop after hormone exposure
desensitization
______ increases sensitivity in cells and increases rate of receptor synthesis
upregulation
What are the 3 types of hormone interactions?
permissive
synergistic
antagonistic
What hormone reaction involves hormones helping each other (without theres a weaker response)
permissive interaction
(TH making Epi receptors in heart)
What hormone reaction involves 2+ hormones having an increased response compared to 1 hormone on the target tissue?
synergistic interactions
(FSH, LH work together)
What hormone reaction involves hormones that oppose each other (Tight regulation of specific parameter)?
antagonistic interactions
(calcitonin, PTH)
Drugs with similar design compete for _____ ______
same receptor
Drug that binds to receptor and leads to activation
agonist
drug that binds receptor and causes inhibition of action
antagonist
Meds in inhalers mimic ___
epi (bronchioles relax)
Meds that prevent stroke antagonize ___
Epi
(prevent blood vessel block
