Autonomic NS Flashcards
ANS is a division of CNS/PNS?
PNS
3 divisions of ANS
parasympathetic, sympathetic, enteric
somatic NS consists of
single motor neuron and the skeletal muscle fiber it innervates
cell bodies of somatic cells are found
in brain stem or spinal cord
presynaptic terminals release _____
Ach
efferent synapses are found…
on skeletal muscle (effector organ)
where are sympathetic chain ganglia
ventral and lateral to spinal cord from cervical to coccyx
are white or grey ramus communicans myelinated?
white; FAST
ramus communicans
connections from spinal cord TO ganglia then OUT to periphery
ALL preganglionic sympathetic neurons travel through _______
white ramus communicans
is input or output myelinated to sympathetic chain ganglia?
input; white ramus communicans
where are prevertebral ganglia located
in front of vertebral column near the organs they innervate
where would the preganglionic sympathetic neurons for organs in the thorax be located?
upper thoracic spinal cord
what ganglia are the largest in the ANS?
the 2 celiac ganglia
branches of prevertebral ganglia
celiac, aortia-renal, superior and inferior mesenteric ganglia
prevertebral ganglia are associated with what general functions
control organs in abdominal cavity, are part of enteric NS
another word for presynaptic
preganglionic
adrenal medulla is a mixture of…
endocrine organ and sympathetic ganglia (preganglionic)
1 ganglia in body that does not follow normal pattern
adrenal medulla; its part endocrine organ
are pre/postganglionic neurons cholinergic/adrenergic
preganglionic: cholinergic
postganglionic: adrenergic
cholinergic neurons release_____ which binds to _____
Ach; nicotinic receptors
adrenergic neurons release _______ which binds to ______
norepi; adrenergic
4 types of adrenergic receptors
a1, a2, b1, b2
1 exception to adrenergic neurons
when targeting sweat glands, Ach binds to muscarinic receptors on gland
neuroeffector junctions
synapse between nerve/target tissues where postganglionic motor neuron releases NT
varicosities are a reason for _____ precision but _____ speed
less precision; more speed
varicosities
branching at axons that allows for incr surface area for NT release; coordinate contraction
sympathetic NS gross responses on body
incr HR, ventilation, BG; decr GI motility, direction of blood away from skin and splanchnic directed to sk musc
what structure sets the sympathetic tone of body
adrenal medulla
adrenal medulla synapses on______, releasing ______, activating release of _________
chromaffin cells, release ACh, nicotinic receptors activate and release epi/norepi
epi/norepi release ratio?
epi 80%
norepi 20%
what enzyme converts norepi->epi
PMNT (phenylethanolamine-N-methyltransferase)
ganglia of parasympathetic NS are located near
or on target organs
parasympathetic neurons originate from
cervical and sacral regions (CNs and S2-S4)
nicotinic receptors are really…
ligand-gated Na channels
how do the symp/parasymp work together in saliva secretion?
parasymp: incr aqueous component
symp: incr enzymatic component
pacemaker of heart? symp/parasymp stimulus?
SA node
symp: incr HR
parasymp: decr HR
what role do baroreceptors play in SA node signals
they detect BP, send to vasomotor center of brainstem; parasymp/symp regulate HR
micturition
emptying bladder; external sphincter is skeletal muscle (voluntary)
micturition reflex
sense of bladder being full= ANS control
what 2 parts of bladder are under symp control during filling
detrusor muscle (wall of bladder) relaxing, constriction of internal sphincter
when bladder is empty/full does parasympathetic control dominate?
full; sensed by mechanoreceptors->spinal cord->brainstem->contract detrusor, relax internal sphincter
regions of the brain regulating ANS
hypothalamus and brainstem
brainstem centers are responsible for
temp regulation, thirst and food intake, micturition, breathing, vasomotor, swallow, cough, vomit
ultimate outcome of alpha1 activation
release of Ca2+
tissues with activated B1 receptors results in _______ or ______
increase or contraction
tissues with activated B2 receptors will result in ______ or ______
relaxation or dilation
an increase in intracellular cAMP will either stimulate ______ or _______
increase contractility OR smooth muscle relaxation
which receptor is responsible for incr HR, cardiac output, and BP
B1
which receptor is responsible for redistribution of blood away from skin, kidneys, and splanchnic region towards sk muscle
B2
which receptor is responsible for incr ventilation, dilation of airways
B2
which receptor is responsible for decreased gastrointestinal motility and secretions
B2
which receptor is responsible for increased blood glucose concentration
a1
is NE or Epi more dominant over a1 receptors
NE
is NE or epi more dominant over a2 receptors
epi slightly
adrenal medulla dominates _____ receptors
a2
is epi or norepi more dominant over B1 receptors?
they are equal
is epi or norepi more dominant over B2 receptors?
epi!!!
Ach receptors are __________ and __________
integral membrane protein; ion channel for Na/K
M2 receptors make it more difficult for cells to reach _______
threshold
agonists _________ a receptor
stimulate
antagonists _________ a receptor
inhibit
what does B1 activation do to HR
increase
what would propanolol (antagonist) do on B1 to HR
decrease HR
what does the parasymp NS via M2 receptors do to HR
slows
what would atropine (antagonist) do on M2 receptors to HR
incr HR
