ANS Flashcards
define the ANS
portion of CNS and PNS that is responsible for unconscious control of visceral function
2 divisions of ANS
parasympathetic and sympathetic
What fibers can “feel fullness” aka distention
vagal sympathetic afferents
What division of the cord is sympathetic? parasympathetic?
sympathetic- thoracolumbar
parasympathetic- craniosacral
Where are the secondary neurons in autonomic neurons
in peripheral ganglia
What are the 4 peripheral ganglia for the cranial portion of PANS
ciliary III
pterygopalantine VII
submandibular VII
otic IX
Are the vagal and sacral ganglia of PANS named?
no, found in walls of organs innervated
What are the 2 types of sympathetic ganglia
Paravertebral and pre-vertebral ganglia
Describe paravertebral ganglia
sympathetic trunk chain ganglia- attached to spinal nerves by rami communicans
What do white ramus communicans carry
myelinated preganglionic sympathetic fibers from a spinal nerve to a paravertebral ganglion
What do gray ramus communicans carry
conduct unmyelinated post-ganglionic sympathetic fibers from paravertebral ganglion to a spinal nerve
describe pre-vertebral ganglia
located anterior to the vertebral column(ant to aorta)
celia, aorticorenal, superior and inferior mesenteric ganglia as well as scattered ganglial cells which exist in autonomic plexuses of the kidney and pelvis
Describe preganglionic fiber
efferent fiber from preganglionic neuron
describe postganglionic fiber
from the second neuron( bodies in peripheral ganglion)
What is the splanchnic nerve
sympathetic preganglionic fiber that does not synapse in paracertebral ganglion
synapse distally to a prevertebral ganglion closer to organis which they innervate
Describe pathway of preganglionic sympathetic fibers
enter sympathetic chains ganglia via white rami communicans and either synapse at that level and exit gray rami communicans or ascend/descend a few segments
also! can pass through sympathetic chains and ganglion to pass via splanchnic nerve to a pre-vertebral ganglion
Head and Neck sympathetic distribution
T1-T4
Thorax sympathetic distribution
T1-T6
Upper Limb sympathetic distribution
T2-T7
Abdomen sympathetic distribution
T5-L2
Pelvis and Perineum sympathetic distribution
T11-L2
Lower limb sympathetic distribution
T10-L2/L3
How do parasympathetic pre-ganglionic fibers travel
through CN and via plexuses on surface of organs.
Which spinal nerve is the exception and carries PANS fibers
pelvic splanchnic nerves S2-4
Which autonomic fiber does not exist in plexuses on surfaces of arterial blood vessels
postganglionic PANS
Differences in the ratio of post vs preganglionic fibers ins SANS and PANS
post:pre is much greater in SANS versus the PANS
global effects of SANS
local effects PANS
What mediates the preganglionic synapse with postganglionic neuron
Ach for both SANS PANS
What mediates the postganglionic synapse with effector organ
PANS- Ach
SANS- Norepi
How is acute visceral pain better localized
pain fibers parallel the preganglionic sympathetic fibers that arise from specific segments so enter at same level
Referred pain with dermatomes is limited to what levels
T1-L2 because these afferent pain fibers travel with sympathetic visceral motor system
Viscerosomatic reflex
visceral afferent stimulation results in somatic responses. usually increased sympathetic tone.
