ANS Flashcards
Autonomic nervous system
autonomic NS
motor pathway includes 2 neurons; preganglionic and postganglionic
sympathetic NS
thoracolumbar; fight or flight;
axons exit through ventral roots of spinal nerves
preganglionic fibers SNS
leave spinal nerves through white rami into sympathetic ganglia
postganglionic fibers SNS
extend out from sympathetic ganglia to visceral effectors
adrenal gland exception
some preganglionic fibers extend to adrenals to release norepinephrine and epinephrine
parasympathetic NS
craniosacral; CN III, VII, IX, X, S2-4; preganglionic long and myelinated, postganglionic are short and unmyelinated
cholinergic fibers
fibers that secrete acetylcholine; preganglionic fibers; postganglionic parasympathetic fibers; sympathetic postganglionic sweat glands; sympathetic fibers in blood vessels to muscles and skin
adrenergic fibers
fibers that secrete norepinephrine; most postganglionic sympathetic fibers
adrenergic receptors
on effector cells; alpha 1,2 and beta 1,2
alpha 1 receptor
post synaptic, vascular smooth m., stimulation = vasoconstriction, increases BP
alpha 2 receptor
presynaptic, auto-inhibitory to NE release, vascular smooth m., decreases BP
beta 1 receptor
post synaptic; cardiac m., increases heart rate
beta 2 receptor
post synaptic; nonvascular smooth m., respiratory, digestive, uterine
blood pressure
= HR x SV x TPR
atropine
anticholinergic; suppress salivation and respiratory secretions
