Autonomic NS Flashcards
whats the difference between autonomic and somatic NS
autonomic occurs unconsciously
there is an extra autonomic ganglion, spreads signal more widely
what neurotransmitter is used in the sympathetic pathway
norepinephrine and acetylcholine
what receptor is acted on in the sympathetic pathway
adrenergic receptor
what neurotransmitter is used in the parasympathetic pathway
acetylcholine
what receptor is acted on in the parasympathetic pathway
muscarinic receptor
what receptor is acted on in autonomic ganglion
nicotinic
Some nerves originating in the lateral horn of the spinal cord at L2/3, travel down the vertebral column (in cauda equina) to emerge between vertebrae S2-4
These nerves synapse in a parasympathetic ganglion and therefore carry
parasympathetic fibres
ffs
what is a mass distribution mechanism for sympathetic supply to all parts of the body
Paravertebral paired sympathetic ganglia –
on each side of the vertebral bodies from C1 – S5 sympathetic chain
explain how sympathetic fibres travel
- travel in ventral root of spinal nerve to mixed spinal nerve (MSN)
- leave the MSN via a white ramus communican as preganglionic fibres to enter the sympathetic ganglion of the same vertebral level
- synapse in ganglia, re-enter the spinal nerve via the grey rc as postganlionic fibres
- distributed in both dorsal and ventral rami of the spinal nerve.
- rami go supply skin and body
how do parts of the body above and below T1-L2/3 receive sympathetic innervation?
Preganglionic fibres can travel up or down the sympathetic chain from between vertebral levels T1-L2/3 without synapsing there, synapse at sympathetic ganglia higher or lower and enter the spinal nerve occurring at that vertebral level
where are sympathetic neurons
cell bodies in the lateral horn
T1-L2/3
what allows the mass response of the sympathetic NS
ability to move superiorly and inferiorly along the sympathetic chain
what 3 options are available to sympathetic fibres in the sympathetic chain
1) they can synapse in the chain at the same level
2) they can run up or down the chain and synapse at a different level
3) they can pass straight through the chain and synapse elsewhere, eg. in an autonomic nerve ganglion or plexus in the thorax or abdomen
what are splanchnic nerves
Sympathetic preganglionic fibres which travel to supply organs
what do splanchnic nerves to thoracic organs do and where do they come from
from T1-T4
synapse in the sympathetic chain, and then run as postganglionic fibres to the organ.
what do splanchnic nerves to abdominal organs do and where do they come from
from T5-L2/3
do not synapse in the sympathetic chain
pass as preganglionic fibres that synapse instead in preaortic ganglia outwith the sympathetic chain, and and then run on from there as postganglionic fibres to supply the organ.
in the sympathetic supply to face and head, what 3 ganglia do they synapse in
superior cervical ganglia C1
middle
inferior C8/T1
what is the autonomic sensory supply
pain impulses run with sympathetic fibres
enter dorsal root of spinal nerve, synapse in dorsal root ganglion and continue to dorsal horn of spinal cord up spinal cord to brain
where do parasympathetic fibres arise from
S2-4
3rd, 7th, 9th and 10th cranial nerve
what are the pelvic splanchnic nerves
the S2, S3, and S4 spinal nerves carrying parasympathetic fibres to pelvic organs
where do the pelvic splanchnic nerve cell bodies reside
reside in the lateral horn of the spinal cord in the L2-3 spinal segments.
how do parasympathetic fibres travel
preganglionic axons exit vertebral column at cauda equina as S2-4 spinal nerves
run through the pelvic/inferior hypogastric plexus (a mixed sympathetic & parasympathetic distributing network) to synapse in a parasympathetic ganglion close to or within the target organ.
where is the ganglion in sympathetic fibres
near the spinal cord, short preganglionic fibres
where is the ganglion in parasympathetic fibres
close to the target organ
long preganglionic fibres
