autonomic nervous system Flashcards
What does the ANS innervate
smooth and cardiac muscle, viscera, and glands
What kind of nervous system is the ANS
involuntary efferent motor nervous system
what is the main goal of the ANS?
to maintain homeostasis in the bodyb
compare and contrast sympathetic vs parasympathetic nervous systems
SAME:
- both divisions of the parasympathetic nervous system
- most organs are innervated by both
DIF
- functionally and anatomically distinct
- generally opposing effects
- symp is more active in times of stress and exertion and emergancy
- para is more active under restign conditions
what are the functions of the sympathetic nervous system
to stimulate metabolism to release glucose stores during stress exertion and emergencies. Also increases HR, force of contraction, and blood pressure. while down regulating digestion and dialating blood vessels
what are the functions of the parasympatheic nervous system
promote relaxation, nutrient uptake, and energy storage by decreasing heart rate, force of contraction, and blood pressure while dialating blood vessels in GI tract and stimulating digestion and gut motility
what is a myelin sheath?
a lipid- rich sheath that surrounds nerve cell axons and acts as an insulating layer
why do some neurons have myelin sheaths?
to increase the velocity of their signals
in the somatic efferent system where is the cell body
the ventral horn
in the somatic efferent system how many neurons are there btw CNS and target
one
in the autonomic efferent system where is the pre ganglionic cell body
spinal cord or brain stem nuclei
in the autonomic efferent system how many neurons are there btw CNS and target
two
in the autonomic efferent system what is the ganglion called?
autonomic ganglion
in the ANS where is the post ganglionic cell body?
autonomic ganglion
in the ANS is the pre ganglionic neuron myelinated?
YES!
in the ANS is the psot ganglionic neuron myelinated?
NO!
What is a ganglia
a collection of neuronal cell bodies found in the PNS
what is a DRG
sensory (afferent) ganglion of somatic nervous sysem
what is the main function of ganglia in the ANS
to act as relay stations btw the pre and post ganglionic neurons
what are the outflow regions of the sympathtic nervous system
thoraco-lumbar - T1 to L2
what are the outflow regions of the parasympathetic nervous system
cranio-sacral. so cranial nerves 3, 7, 9, and 10 as well as sacral regions S2-S4
how are the sympathetic chain ganglia oriented?
they are connected to one another (paired_) along length of vertebral column (C1-S5)
why is the orientation of sympathetic chain ganglia important?
having the sympathetic chain ganglia connected to one another coordinates and spreads sympathetic responses to many tissues simultaneously
what are the 3 pre vertebral ganglia of the sympathetic chain?
celiac ganglion, superior mesenteric ganglion, inferior mesenteric ganglion
what are rami communicans?
connections btw spinal nerve and sympatetic trunk
where does sympathetic outflow oringinate?
lateral horn of the spinal cord from segments T1-L2 as this is where the pre ganglionic neuron begins
how does the sympathetic preganglionic neuron exit the spine
ventral horn and root to become a spinal nerve
how does the sympathetic preganglionic neuron enter the sympathetic chain
white ramus comminicans
once the preganglionic neuron has entered the sympathetic chain - what happen next
it can either:
1. synapse with the chain at the same level and exit with gray ramus, traveling with spinal nerve
2. change levels within the chain and then synapse
3. form a splanchnic nerve
what do preganglionic neurons that stay at the same level in the sympathetic chain target
body wall, ab and thoracic viscera, and limbs
what do pre ganglionic neurons that ascend or descend within the sympathetic chain tagrte?
ascending nerves target: head and neck viscera, thoracic viscera, upper limbs
descending nerves target: abdominopelvic viscera, lower limbs
what plexuses do the post ganglionic neurons of the symapthetic chain contribute to?
cardiac plexus and the piulmonary plexusq
what is a splanchnic nerve?
visceral nerve - typically associated with abdominopelvis viscera
when do sympathetic splanic nerves form?
when autonomic fibers do to rejoin spinal nerves and instead bypass the sympathetic chain
in the sympathetic system where do the paired splanic nerves originate from?
thoracic and lumbar vertebral levels
where do sympathetic splanic nerves synapse?
in the pre vertebral ganglia of the sympathetic chain
where does the greater splanic nerve come from?
T5-T9
where does the lesser splanic nerve come from?
T10-T11
where doe the least/lumber splanic nerve come from?
T12-L2
which ganglion does the greater splanichnic nerve innervate with?
celiac ganglion
which ganglion does the lesser splachbnic nerve innervate with
superior mesenteric ganglion
which ganglion does the least splanchnic nerve innervate with
inferior mesenteric gangliojn
what are the targets of the parasympatehtic nervous system?
viscera of the head and neck, abdominal and thoracic viscera, and pelvic viscera
what is a big difference with regards to the pre ganglionic neuron in the parasympathetic vs sympathetic nervous system
in the parasympathetic nervous system, the pre-ganglionic neuron is long bc the parasympathetic ganglia are near or within the target.
In the sympathetic nervous system, the sympathetic ganglia are located near the vertebral column so the preganglionic neurons are short
what is a big difference with regards to the post ganglionic neuron in the parasympathetic vs sympathetic nervous system
in the parasympathetic nervous system, the post-ganglionic neuron is short bc the parasympathetic ganglia are near or within the target.
In the sympathetic nervous system, the sympathetic ganglia are located near the vertebral column so the post ganglionic neurons are long
which cranial nerves carry parasympathetic fibers
3, 7, 9, 10
what does a visceral reflex arc consist of?
sensory nerve and visceral motor neurons
what is the enteric nervous system
network of neurons located in walls of digestive tarct
