ANS Flashcards
ANS Parasymp fibers?
Release what neurotrans?
Long pre-gang from cranial and sacral:
release ACh
Short post-gang near organ:
release ACh
ANS Symp fibers?
Release what neurotrans?
Short pre-gang in thoracic and lumbar:
release ACh
Long post-gang at target:
release NE
ACh released by which fibers? (5)
All pre-gang Parasymp post-gang Symp to sweat glands At adrenal medulla Somatic to mm
Norepi released by which fibers?
Symp post-gang (except sweat glands)
Adrenal medulla
Dopamine released by?
renal vasculature
5 steps in neurotrans fxn?
1) synthesis
2) storage
3) release
4) receptor interaction
5) inactivation
ACh made how?
Choline + Acetyl CoA -> ChAT enz -> ACh
ACh inactivated by?
acetylchoninesterase
Adrenergic (epi) transmission cycle?
Tyrosine into terminal ->
∆ to DOPA then dopamine ->
∆ to NE ->
released to receptors
DOPA synth blocked by?
metyrosine
NE in vesicle depleted by?
reserpine
NE re-uptake blocked by?
cocaine and TCAs
NE release ↑ by?
amphetamines, tyramine
but only if terminal is intact
NE metabolized by?
MAO and COMT
Cholinergic receptors? (4)
M1: sweat glands, CNS
M2: heart, smooth mm, presynaptic
M3: exocrine, smooth mm, endothelium
Nicotinic: Na+ channel, Nn, Nm
Cholinergic receptors controlled what:
M1
M2
M3
M1 and M3: Gq/11; PLC, IP3, DAG
M2: Gi; inhibits adenylyl cyclase
Adrenergic receptors? (5)
α1: smooth mm, excitatory α2: presynap terminals, some smooth mm β1: heart β2: heart, bronchioles, skeletal mm blood vessles β3: fat cells (lypolysis)
Adrenergic receptors control what:
α1
α2
all β
α1: Gq; PLC, IP3, DAG
α2: Gi; inhibits adenylyl cyclase
all β: Gs; stim adenylyl cyclase
Dopamine receptors?
D1, D5: brain, vascular bed
D2, D3, D4: brain, other tissues
Dopamine receptors controlled what:
D1, D5
D2, D3, D4
D1, D5: ↑ cAMP
D2, D3, D4: ↓ cAMP
Down-Regluation is?
constant stim w/ agonist causes:
↑ destruction of receptors or
∆ in affinity which ↓ receptor response
Up-Regulation is?
lack of stim causes:
# of receptors to ↑ or response of receptor to ↑
Parasymp response in:
heart, bv, lungs
↓ HR and AV conduction (M2)
bronchoconstriction (M3)
Symp response in:
heart, bv, lungs
↑ HR, AV conduction and contractility (β1)
bronchodilation (β2)
bv constriction (α1)
Parasymp response in:
glands, eyes
miosis, accommodation
↑ mucus, salivation, lacrimation
(M3)
Symp response in:
glands, eyes
mydriasis, vasoconstriction, salivation (α)
sweating (M1)
Parasymp response in:
GI
↑ hydrochloric acid secretion,
↑ motility,
relax sphincters
(M3)
Symp response in:
GI
glycogenolysis (β2),
↓ motility (α2, β2)
Parasymp response in:
GU
contract bladder,
relax sphincters,
promote erection
(M3)
Symp response in:
GU
renin secretion (β1),
relax bladder and uterus (β2),
contract sphincters, ejaculation (α1)
Baroreceptor reflex initiated by?
NE release:
α causes vasoconstriction
β1 ↑ HR/contractility
= ↑ arterial pressure
Baroreceptor response to ↑ arterial pressure in aortic arch?
↑ afferent impulse to medulla:
↓ symp -> vasodialtion
↑ parasymp -> ACh release -> ↓ HR and CO
Muscarinic receptors in ciliary mm do what?
constrict = lens rounds
Pupil size controlled how?
Symp stim of α1 receptor in iris radial mm = contract to dilate pupil
Parasym stim of M3 receptor in iris circular mm = contract to constrict pupil
Summary of eye: Muscarinic Agonists do?
contract circular mm (constriction),
contract ciliary mm (accommodation),
↑ outflow aqueous humor into canal of Schlemm,
↓ intraocular pressure
Summary of eye: Adrenergics do?
contract radial mm (dilation),
↑ prodxn aqueous humor,
↑ intraocular pressure
