Exam 4 Flashcards
(24 cards)
“fight or flight”
sympathetic nervous system
“rest and digest”
parasympathetic nervous system
which neurotransmitter is released by the preganglionic fibers of the SNS?
acetylcholine
what receptor on the SNS postganglionic fiber receives ACh from the presynaptic fiber?
nicotinic receptor
which fibers of the SNS are short?
preganglionic
which fibers of the SNS are long?
postganglionic
what neurotransmitter is released from the postganglionic fibers of the SNS?
(mostly) norepinephrine
what type of receptor on the effector organ receives NE from the postsynapatic fiber in the SNS?
adrenergic receptor (alpha/beta)
what neurotransmitters do adrenergic receptors accept?
norepinephrine
epinephrine
dopamine
which neurotransmitter causes a negative feedback loop in the SNS?
norepinephrine
describe how norepinephrine is synthesized
tyrosine –> DOPA –> dopamine –> norepinephrine
what is the rate-limiting step in the synthesis of norepinephrine?
conversion of tyrosine –> DOPA
which enzyme catalyzes the transformation of tyrosine to DOPA?
tyrosine hydroxylase
what happens to convert dopamine to norepinephrine?
dopamine is beta-hydroxylated
what happens to convert norepinephrine to epinephrine?
norepinephrine is methylated in the adrenal medulla
what are the three ways norepinephrine is metabolized?
- reuptake by postganglionic fiber
- degraded by MAO or COMT
- dissolves away
how much epinephrine vs norepinephrine is released from the adrenal medulla?
80% epinephrine
20% norepinephrine
which cranial nerves does the PNS arise from?
CN III
CN VII
CN IX
CN X
what type of receptors on the postganglionic fibers receive ACh from the preganglionic fibers in the PNS?
nicotinic receptors
in the PNS, what are the receptors on the target/effector organs that receive ACh from the postganglionic fibers?
muscarinic receptors
how is acetylcholine metabolized?
cleaved by acetylcholinesterase into acetate ion and choline
what does alpha 1 stimulation cause?
vasoconstriction, increased SVR
what does beta 1 stimulation cause?
increased inotropy, chronotropy, and conduction
what does beta 2 stimulation cause?
smooth muscle relaxation in the vasculature and in the bronchial tree?
