ANS anatomy & physiology 2 Flashcards
Which anatomic pattern is characteristic of sympathetic efferent pathways?
a. long preganglionic fibers, long postganglionic fibers
b. long preganglionic fibers, short postganglionic fibers
c. short preganglionic fibers, short postganglionic fibers
d. short preganglionic fibers, long postganglionic fibers
d. short preganglionic fibers, long postganglionic fibers
The SNS originates from the
spinal cord levels T1-L2 (L3) and thus is also known as the thoracolumbar division
Preganglionic sympathetic neurons exit the spinal cord through
ventral roots
Postganglionic sympathetic neurons are distributed from the
relay ganglia through spinal nerves and visceral plexuses
Visceral plexuses are usually associated with
major arterial branches of the aorta
The characterization of the SNS anatomy is the
short preganglionic, long postganglionic
SNS innervation to the ______________ is a direct path from the spinal cord to the tissue with no relay ganglia in this pathway.
adrenal medulla
Blockade of the stellate ganglion produces
Horner syndrome
Horner syndrome is characterized by
ipsilateral ptosis
miosis
anhidrosis
flushing of the skin
nasal congestion
enophthalmos
What is the anatomic organization of the ANS?
Origin: preganglionic nerve cell body (soma)
route to relay: preganglionic axon
Relay: ganglion
distribution: postganglionic axon
Effector (target): tissue or organ
In both sympathetic and parasympathetic divisions, the origins of ALL preganglionic autonomic neurons lie in
the CNS
The cell bodies (soma) of preganglionic sympathetic fibers are located within the
lateral horn of the spinal cord grey matter, specifically within the intermediolateral nucleus
The interomediolateral nucleus lies in
Rexed’s lamina 7
The PNS division originates in
cranial and sacral regions of the CNS
The parasympathetic division is also known as the
craniosacral system
The axons of preganglionic sympathetic neurons leave the spinal cord at the
segmental level at which their cell bodies are located
White rami exist only at _________ because all preganglionic sympathetic fibers originate from T1-L2
only at T1-L2
The somatomotor division arises (origin) in the
ventral horn of the spinal cord (Rexed’s 8 & 9)
The axons of some preganglionic sympathetic neurons project ______________ and synapse with a postganglionic sympathetic neuron in a sympathetic trunk relay ganglion at the __________________ of the preganglionic origin
ipsilaterally; at the same cord level
Grey rami are found at
all spinal cord levels
The axons of some preganglionic neurons travel ______________ or ________________ in the sympathetic trunk (aka sympathetic chain or paravertebral ganglia) to synapse on ipsilateral sympathetic postganglionic nerve cells bodies in sympathetic trunk relay ganglia _________________________________
rostrally (ascend) or caudally (descend); some distance from the cord level of origin
A third possible trajectory of preganglionic sympathetic axons is to __________________ without interruption to synapse then on postganglionic sympathetic nerve cells bodies in ___________________ relay ganglia located near abdominal or pelvic visceral targets they innervate
pass through paravertebral ganglia (sympathetic chain or trunk); prevertebral (aka peripheral or collateral)
Route 3 to relays preganglionic sympathetic axons (B fibers) traverse uninterrupted through the sympathetic trunk and associate to form
splanchnic nerves
The fourth and last route is for the sympathetic preganglionic fibers that project
directly to and terminate on an effector (target)
Route 4 has no
synaptic relay
The target tissue of the route four relay is
chromaffin cells of the adrenal medulla
The sympathetic trunks are
bilateral; one on each side of the vertebral column, and run the full length of the column
The sympathetic chain ganglia pairs are:
3 cervical (superior, middle, inferior)
11-12 thoracic
3-5 lumbar
3-5 sacral
single coccygeal
The stellate (cervicothoracic) ganglion is a combination of the
inferior cervical ganglion and T1 ganglion
The lumbar sympathetic ganglia may be blocked temporarily or semi-permanently to treat a variety of disorders including
symptomatic vasospastic disorders; CPRS 1 & 2 of the lower extremity; phantom limb and stump pain
pain from shingles, and acute & chronic renal cholic
The thoracic splanchnic nerves consists of:
greater splanchnic nerve arising from T5-T9/T10
lesser splanchnic nerve from T10-T11
Least splanchnic nerve from T12
The greater splanchnic nerve of the thoracic splanchnic nerves travels to the
celiac and superior mesenteric ganglia and the prevertebral plexus
The lesser splanchnic nerve of the thoracic splanchnic nerve travels to the
celiac, aorticorenal, and superior and inferior mesenteric ganglia and prevertebral plexus
The least splanchnic nerve of the thoracic splanchnic nerve projects to the
renal plexus
The lumbar splanchnic nerves travel to the
inferior mesenteric ganglion and prevertebral plexus
The sacral splanchnic nerves pass from the sacral part of the sympathetic trunk and enter the
inferior hypogastric plexus
Pelvic splanchnic nerves are unique in the fact that they are the only splanchnic nerves to carry
parasympathetic fibers
The pelvic splanchnic nerves ____________________ from the sympathetic trunks
DO NOT originate
The abdominal prevertebral plexus is a collection of plexuses that
surrounds the abdominal aorta
The abdominal prevertebral plexus is composed of
celiac plexus and celiac ganglia
superior hypogastric plexus
aortic plexus with superior mesenteric and aorticorenal ganglia
Local anesthetic block of the celiac plexus may be used in
acute and chronic pancreatitis or in conjunction with a nerve block of the lower intercostal nerves to produce regional anesthesia for intra-abdominal surgery
As a result of divergence and convergence in the ganglia, information from the CNS may be
amplified or reduced and may be wither localized or diversified
The intermediolateral nucleus lies within which Rexed’s lamina?
Rexed’s lamina 7
Which ganglia are sites for sympathetic synaptic relays?
sympathetic chain ganglia & prevertebral ganglia
What is ganglion?
a peripheral collection of nerve cell bodies
List the three thoracic splanchnic nerves.
The greater, lesser, and least splanchnic nerves
Which plexus may be blocked for relief of pain due to chronic pancreatitis?
celiac plexus
