somatic
motor neuron neurotransmitters – ACh (acetylcholine) only
autonomic
motor neuron neurotransmitters – ACh or NE (norepinephrine a.k.a.
noradrenaline)
2
principal branches of ANS have opposing actions
sympathetic NS = thoracolumbar
division / outflow (T1-12, L1-2)
vertebral chain
(a.k.a. sympathetic trunk, a.k.a. paravertebral) ganglia
prevertebral (a.k.a.
collateral) ganglia
parasympathetic NS =
craniosacral division / outflow (S2-4, brainstem)
terminal (a.k.a.
intramural) ganglia
autonomic
plexuses – tangled networks of sympathetic & parasympathetic neurons
_____________________________________________________________________________________________
SYMPATHETIC
O---< ACh (nicotinic) O------------------------------< NE (adrenergic) (most effectors)
PARASYMPATHETIC
O--------------------------------<
ACh (nicotinic) O---< ACh (muscarinic) (effectors)
_____________________________________________________________________________________________
cholinergic
neurons – release ACh, cholinergic
receptors – bind ACh
(cholinergic) nicotinic receptors
– sympathetic
& parasympathetic neurons and also motor end plates
(cholinergic) muscarinic receptors
–
parasympathetic effectors (and
very few sympathetic effectors = sweat glands)
adrenergic
neurons – release NE, adrenergic
receptors – bind NE
agonist
– binds to & activates receptor (mimics neurotransmitter)
antagonist
– binds to & blocks receptor (prevents neurotransmitter from having effect)
hypothalamus
– regulates balance between sympathetic tone & parasympathetic tone
SYMPATHETIC
STIMULATION PARASYMPATHETIC
STIMULATION
[ α
or β (adrenergic) receptors ] [ muscarinic (cholinergic)
receptors ]
FIGHT
or FLIGHT FEED and BREED /
REST and DIGEST
INHIBITS
DIGESTION PROMOTES
DIGESTION
inhibits
digestive enzyme secretion & digestive juices promotes
digestive enzyme secretion &
digestive juices
decreases
GI motility increases GI motility
contracts
sphincters
increases
activity / release of hormones & enzymes increases
glycogen synthesis
for breaking down glycogen &
triglycerides
INHIBITS
URINATION PROMOTES
URINATION
increases
ADH - antidiuretic hormone
relaxes
bladder wall contracts bladder wall
contracts
sphincter relaxes sphincter
INCREASES
WORK OF HEART DECREASES
WORK OF HEART
increases
heart rate & force of contraction decreases heart rate & force
of contraction
INCREASES
WORK OF LUNGS DECREASES
WORK OF LUNGS
dilates
airways constricts airways
PUPIL
DILATES PUPIL CONSTRICTS
INCREASES
SEXUAL ACTIVITY
vasodilation
in clitoris and penis