Autonomic NS

Question 1

whats the difference between autonomic and somatic NS

Answer 1

autonomic occurs unconsciously

there is an extra autonomic ganglion, spreads signal more widely

Question 2

what neurotransmitter is used in the sympathetic pathway

Answer 2

norepinephrine and acetylcholine

Question 3

what receptor is acted on in the sympathetic pathway

Answer 3

adrenergic receptor

Question 4

what neurotransmitter is used in the parasympathetic pathway

Answer 4

acetylcholine

Question 5

what receptor is acted on in the parasympathetic pathway

Answer 5

muscarinic receptor

Question 6

what receptor is acted on in autonomic ganglion

Answer 6

nicotinic

Question 7

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

Answer 7

ffs

Question 8

what is a mass distribution mechanism for sympathetic supply to all parts of the body

Answer 8

Paravertebral paired sympathetic ganglia –

on each side of the vertebral bodies from C1 – S5 sympathetic chain

Question 9

explain how sympathetic fibres travel

Answer 9

• 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

Question 10

how do parts of the body above and below T1-L2/3 receive sympathetic innervation?

Answer 10

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

Question 11

where are sympathetic neurons

Answer 11

cell bodies in the lateral horn

T1-L2/3

Question 12

what allows the mass response of the sympathetic NS

Answer 12

ability to move superiorly and inferiorly along the sympathetic chain

Question 13

what 3 options are available to sympathetic fibres in the sympathetic chain

Answer 13

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

Question 14

what are splanchnic nerves

Answer 14

Sympathetic preganglionic fibres which travel to supply organs

Question 15

what do splanchnic nerves to thoracic organs do and where do they come from

Answer 15

from T1-T4

synapse in the sympathetic chain, and then run as postganglionic fibres to the organ.

Question 16

what do splanchnic nerves to abdominal organs do and where do they come from

Answer 16

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.

Question 17

in the sympathetic supply to face and head, what 3 ganglia do they synapse in

Answer 17

superior cervical ganglia C1
middle
inferior C8/T1

Question 18

what is the autonomic sensory supply

Answer 18

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

Question 19

where do parasympathetic fibres arise from

Answer 19

S2-4

3rd, 7th, 9th and 10th cranial nerve

Question 20

what are the pelvic splanchnic nerves

Answer 20

the S2, S3, and S4 spinal nerves carrying parasympathetic fibres to pelvic organs

Question 21

where do the pelvic splanchnic nerve cell bodies reside

Answer 21

reside in the lateral horn of the spinal cord in the L2-3 spinal segments.

Question 22

how do parasympathetic fibres travel

Answer 22

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.

Question 23

where is the ganglion in sympathetic fibres

Answer 23

near the spinal cord, short preganglionic fibres

Question 24

where is the ganglion in parasympathetic fibres

Answer 24

close to the target organ

long preganglionic fibres