autonomic nervous system (ch 14) Flashcards
autonomic means
self governed
general aspects of the autonomic nervous system
- motor to smooth muscle, cardiac muscle, glands
- involuntary
two divisions of the autonomic nervous system
sympathetic and parasympathetic
the sympathetic division is
a widespread system with numerous and early branches
function of the sympathetic division
fight or flight, gearing up to expend energy in an emergency
the parasympathetic division is
a smaller, more localized system
function of the parasympathetic division
rest and digest, involved in conserving/storing energy
how many motor neurons come out of the CNS
two - preganglionic and postganglionic
preganglionic motor neurons are
from the CNS to autonomic ganglion, secrete Ach onto a nicotinic receptor in the Na+/K+ ion channel, is lightly myelinated
postganglionic motor neurons are
from the ganglion to the effector, is unmyelinated
NTs for each effector
sympathetic - NE
parasympathetic - ACh
where are ganglia located
sympathetic - usually near spinal cord (pre - short, post - long)
parasympathetic - near/in effector (pre - long, post - short)
output of the sympathetic system
thoracolumbar (regions of the spinal cord)
sympathetic chain ganglia are
paravertebral
the sympathetic goes through
communicating rami that connect sympathetic ganglia to spinal nerves
neurons of the white ramus are
myelinated and preganglionic
neurons/axons of the gray ramus are
unmyelinated and postganglionic
preganglionic fibers may do three things:
- synapse in the same ganglion
- synapse in a higher or lower ganglion
- pass through sympathetic chain ganglia to go to collateral (prevertebral) ganglion
postganglionic axons are found in
- spinal nerves
- sympathetic nerves
- splanchnic nerves
spinal nerves run to
the skin, body surface, and BVs
sympathetic nerves run to
the head and thoracic organs
splanchnic nerves run to
abdominal and pelvic organs
the adrenal medulla is
a highly modified sympathetic ganglion
function of the adrenal medulla
release hormones (chemical messengers) that go into the blood, such as epinephrine (greater quantity) and norepinephrine
epinephrine and norepinephrine are otherwise known as
adrenaline and noradrenaline
these are responsible for cranialsacral output of the parasympathetic system
cranial nerves (oculomotor, facial, glossopharyngeal, vagus) and sacral/lower spinal cord region (S2-S4)
the cranial nerves are responsible for
over 90% of all parasympathetic output
the terminal ganglia are located
near/in the effector organ
if terminal ganglia are in the effector wall, they are called _____
intramural ganglia
neurotransmitters from the preganglionic to postganglionic
are always ACh, send excitatory postsynaptic potential onto nicotinic receptor on the Na+/K+ ion channel, causing it to open
neurotransmitters from the postganglionic to effector organ
sympathetic - norepinephrine
parasympathetic - ACh
receptors for NE/epi
always a 2nd messenger
alpha1: BVs of most organs (not heart)
alpha2: CNS, decreases sympathetic output
beta1: in heart, increases HR and force
beta2: in lungs, dilates tubes/decreases mucus production
beta3: fat, breaks it down to release energy
receptor for ACh
muscarinic receptor (2nd messenger)
most organs have _____ innervations, meaning that _____
dual, sympathetic and parasympathetic oppose/antagonize each other
tone on an effector organ means that
one system predominates
parasympathetic tone examples
heart, GI organs
sympathetic tone example
BVs
S vs P example in eye focus
S: distant vision
P: close vision
S vs P example in pupil size
S: dilate (more light/info)
P: constrict (less light/info)
S vs P example in skin
S: sweat/goosebumps
P: none
S vs P example in heart
S: increase HR/force
P: decrease HR/force
S vs P example in BVs
S: constrict (but dilate to skeletal muscle)
P: none
S vs P example in lung tubes
S: dilation, decrease in mucus production
P: constrict, increase in mucus production
S vs P example in GI
S: decrease saliva, increase % of mucus, decrease GI function
P: opposite
S vs P example in liver (glucose)
S: move or release glucose (glycogenolysis)
P: storing glucose in the form of glycogen
S vs P example in fat
S: breakdown
P: storage
S vs P example in bladder
S: inhibit contraction
P: contraction
S vs P example in genitals
S: orgasm, spinal skeletal muscle reflexes
P: arousal, erection, increased secretion
