Visceral Innervation Flashcards
Neurons in visceral motor pathway
. Pre-ganglionic neuron and post-ganglionic neuron
Pre-ganglionic neuronal cell bodies for visceral motor
. Located in ventro-lateral horns at specific spinal cord levels
. T1-L2 levels for sympathetic neurons
. S2-4 levels for parasympathetic neurons
Preganglionic visceral motor fibers/axons
. Ventral roots
Post-ganglionic neuronal cell bodies for visceral motor nerves
. Autonomic ganglia outside CNS
Parasympathetic division
. Conserve energy and promote normal function
. Localized target and effects
. Both pre and post-ganglionic neurons release neurotransmittter Ach (cholinergic)
. Cell bodies of pre-ganglionic neurons in gray matter of brain stem (vagus) and sacral spinal cord segments (S2-4, craniosacral outflow)
Sympathetic division
. Prepare fight/flight
. Multiple targets and board effects
. Pre-ganglionic neurons release Ach and post-ganglionic neurons release NE(adrenergic)
. Cell bodies of pre-ganglionic neurons in gray matter of thoracic and lumbar spinal cord segments (T1-L3, thoracolumbar outtflow)
Enteric division
. Intrinsic innervation of GI tract located w/in GI walls
.2 complex and interconnected plexuses (meissner and Auerbach)
. 3rd ANS division or parasympathetic component
. Neurons capable of autonomous generation of peristalsis and glandular secretions
. Neurons receive input from parasympathetic and sympathetic divisions
Parasympathetic pre-ganglionic cell body locations
. Brainstorm nuclei assoc. w/ cranial nerve III, VII, IX, and X
. Ventro-lateral horns of gray matter in sacral spinal cord segments S2-4
Route of pre-ganglionic axons coursing in vagus nerve
. In thorax: pre-ganglionic fibers join pulmonary,cardiac, and esophageal autonomic plexuses to distribute to terminal ganglia in walls of lungs, heart, and esophagus
. Esophageal plexus coalesces into ant. And post. Vagal trunks that continue into abdominal cavity
.abdomen: pre-ganglionic fibers (vagal trunks) enter autonomic plexuses assoc. w/ abdominal aorta and branches
. Continues along blood vessels to terminal ganglia in wall of stomach, liver, pancreas, SI, and ascending and transverse colon
Autonomic plexuses
. Bundles of sympathetic, parasympathetic, and visceral sensory fibers coursing to/form common structures
. Named for structures they supply or where they’re located
Route of pre-ganglionic axons/fibers arising in sacral spinal cord segments
. Pre-ganglionic fibers exit S2-4 via ventral roots, spinal nerve proper, and ventral rami
. Branch from ventral rami as pelvic splanchnic nn. That pass to inf. Hypogastric plexuses ain’t hen to sub-plexus specific to pelvic viscera
. Post-ganglion cell bodies: near or w/in walls of target organs
. Post-ganglionic neurons have short axons compared to post-ganglionic sympathetic neurons
T/F There is no parasympathetic n. Distribution to limbs or body wall
T, only supply viscera of head, neck, thorax, abdomen, and pelvis
Splanchnic nerves
. Convey visceral motor and sensory fibers to and from viscera
. Can be parasympathetic or sympathetic
Pre-ganglionic cell body location in sympathetic division
. . Ventro-lateral horns of gray matter is spinal cord segments T1-L2/3 only
Post-ganglionic cell bodies in sympathetic division
. Chain ganglia (paravertebral ganglia): linked by sympathetic fibers to form sympathetic trunks/chains that run along spinal column
. Pre-vertebral ganglia: abdomen and pelvis along abdominal aorta and branches
Pre-vertebral ganglia
. Celiac ganglion: celiac trunk artery and innervates foregut structures
. Sup. Mesenteric, aorticorenal, and inf. Mesenteric ganglia
Route of pre-ganglionic sympathetic fibers
. Exit spinal cord via ventral roots, spinal nerve proper, and ventral rami
. Split as white rami communicantes and enter sympathetic chain (T1-L2/3 only)
Routes w/in sympathetic chain
. Synapse w/ post-ganglionic neuron in chain ganglion at level of entry or course sup/inf. To synapse w/ post-ganglionic neuron in a chain ganglion at different level
. Pass through chain w/o synapsids and merge from chain as thoracic splanchnic nn (T5-12) or lumbarbsplanchnic nn (L1-3) in abdominal cavity, fibers then synapse in pre-vertebral ganglia
Sacral sympathetic splanchnic nn branch fro, chain in pelvic cavity, but _____
Fibers primarily post-ganglionic
sympathetic post-ganglionic fibers
. Long w high number collateral branches for more diffuse widespread effect
Post-ganglion sympathetic fibers in body wall and limbs
. Exit chain as gray rami communicantes (assoc. w/ all spinal nn.)and re-enter spinal nerve proper
. Course w/ dorsal and ventral rami of spinal nn. To their targets
Post-ganglionic sympathetic fibers in head and neck
. Branch directly from sup. Cervical ganglia
. Course along branches of external carotid a. To their targets
Post-ganglionic sympathetic fibers in thoracic organs
. Heart and lungs: split from lower cervical and upper thoracic chain ganglia as sympathetic cardiac nn. And enter cardiac and pulmonary autonomic plexuses to innervates heart and lungs
. Esophagus: split from thoracic chain ganglia and contributes to esophageal autonomic plexus
Post-ganglionic sympahtetic fibers in abdominopelvic viscera
. Arise from prevertebral ganglia and course along blood vessels and through autonomic plexuses to reach target organs
Visceral sensory fibers
. Course retrograde (toward CNS) w/ sympathetic fibers and through white rami communicantes to spinal nerve
. Moves through dorsal root to CNS
. In pelvis, course w/ parasympathetic fibers
The brain interprets pain as ___
Somatic
Where is pain referred to?
Areas of body wall that receive somatic innervation from spinal nerves arises from same spinal cord level
Visceral pain fibers for heart arise from ____
T1-T5 spinal cord levels
Somatovisceral sensory fibers coursing w/ spinal nn. From T1-T6 distribute to ___
Upper limb
Skin sympathetic and parasympathetic effects
. S: raises hair, vasoconstriction, sweating
. P: none
Lacrimal/salivary glands sympathetic and parasympathetic effects
. S: dec. secretion
. P: promotes secretion, makes watery
Eyes S and P effects
S: dilates pupils
. P: contracts pupil, contracts ciliary muscle
Heart S and P effects
S: inc. rate and strength of contractions
P: dec. rate and strength of contractions
Lungs S and P effects
S: inhibits parasympathetic effects which results in bronchodilation
P:constricts bronchi
Digestive tract S and P
. S: inhibits peristalsis, vasoconstriction
. P: stimulates peristalsis and secretions of digestive juices
Urinary tract S and P
S: vasoconstriction, constricts internal urethral sphincter
P: inhibits contraction of internal urethral sphincter, contracts detrusor muscle
Genital tract and organs S and P effects
. S: Causes ejaculation, vasoconstriction causes loss of erection
P: produces engorgement of erectile tissues
Suprarenal medulla S and P effects
S: releases adrenaline into blood
P: none
PNS cranial nn. II, VII, and IX site of synapse and target structures
. Site: 4 pairs of head ganglia
. Target: smooth muscle and glands in head
PNS cranial n. X site of synapse and target structures
. Site: ganglia in/near walls of target structures
. Target: smooth and cardiac muscle, glands of viscera in neck , thorax, foregut, and midgut
PNS pelvic splanchnic nn. Sites of synapse and target structures
Site: ganglia on/near walls of target structures
Target: smooth muscle and glands of hindgut and pelvic viscera
SNS spinal cord levels T1-L2 site of synapse and target structures
. Site: sympathetic chain ganglia
. Target: smooth and cardiac muscle, glands of body wall and limbs (1-L2), head (T1-2), and thoracic viscera (T1-5)
SNS thoracic splanchnic nerves (T5-12) site of synapse and target structures
. Site: prevertebral ganglia
. Target: smooth muscle/glands of foregut and midgut
SNS lumbar splanchnic nn. (L1-3) site of synapse and target structure
. Site: prevertebral ganglia
. Target: smooth muscle/glands of hindgut and pelvic viscera
