autonomic nervous system

Question 1

which are longer in the SNS : presynaptic or postsynaptic fibers

Answer 1

short presynaptic fibers

long postsynaptic fibers

Question 2

what spinal levels does visceral innervation from the SNS come from?

Answer 2

T1-L2 (thoracolumbar)

Question 3

where are the SNS cell bodies for the presynaptic fibers for viscera and parietal structures ?

Answer 3

lateral horn of the spinal cord

Question 4

what is the general pathway SNS pre-synaptic fibers take to the paravertebral ganglion?

(visceral and parietal)

Answer 4

lateral horn–> anterior root–> spinal nerve–> anterior ramus–> white rami communicans–> paravertebral ganglia (where they can synapse)

Question 5

where are the SNS cell bodies for the post synaptic fibers for viscera and parietal structures ?

Answer 5

viscera: paravertebral or prevertebral ganglion

parietal only: paravertebral ganglion

Question 6

where are the paravertebral ganglia?

Answer 6

in the sympathetic chain (sits on either side of the vertebral ganglia)

Question 7

where are the prevertebral ganglia

Answer 7

celiac ganglia, superior mesenteric ganglion, aorticorenal ganglion, inferior mesenteric ganglion

Question 8

what are the synapse options for the SNS pre-synaptic fibers that are going to the viscera?

Answer 8

1. synapse in the paravertebral ganglion on the same level
2. enter paravertebral ganglion -> ascend or descend to another level -> synapse there
3. enter paravertebral ganglion (do not synapse) ->exit through abdominal pelvic splanchnic nerve to prevertebral ganglion and synapse there

Question 9

what structures do parietal fibers innervate?

Answer 9

smooth muscle, skin, blood, sweat glands

Question 10

what is the general pathway SNS parietal post-synaptic fibers travel after they synapse at the paravertebral ganglion?

Answer 10

synapse–> grey rami communicans –> spinal nerve –> anterior or posterior rami (follow somatic nerves)

Question 11

how do SNS parietal post synaptic fibers travel to the trunk (back)?

Answer 11

posterior rami

Question 12

which anterior rami do the SNS parietal post synaptic fibers use to travel to the trunk (anterior/lateral)

Answer 12

intercostal, thoracoabdominal, subcostal

Question 13

how do SNS parietal post synaptic fibers travel to the head/neck/upper extremities

Answer 13

enter paravertebral ganglion –> ascend–> synapse at the cervical sympathetic trunk –> grey rami communicans –> spinal nerve –> anterior rami

Question 14

how do SNS parietal post synaptic fibers travel to the posterior neck

Answer 14

posterior rami

specifically sub occipital n, greater occipital n, least occipital n.

Question 15

which anterior rami do SNS parietal post synaptic fibers use to travel to the head and face

Answer 15

carotid nerves that go to the carotid periarterial plexus

Question 16

which anterior rami do SNS parietal post synaptic fibers use to travel to the anterior neck/upper extremity

Answer 16

cervical plexus/brachial plexus

Question 17

how do SNS parietal post synaptic fibers travel to the perineum/lower extremity

Answer 17

enter paravertebral ganglion –> descend–> synapse at new level of abdominal/sacral sympathetic trunk–> grey rami communicans –> spinal nerve –> anterior rami

Question 18

which anterior rami do SNS parietal post synaptic fibers use to travel to the buttocks?

Answer 18

cluneal nerves

Question 19

which anterior rami do SNS parietal post synaptic fibers use to travel to the perineum/lower extremity?

Answer 19

lumbar/sacral plexus

Question 20

which are longer in the PSNS : presynaptic or postsynaptic fibers

Answer 20

long presynaptic fibers

short post synaptic fibers

Question 21

what are the pre-synaptic fibers for the PSNS?

Answer 21

craniosacral nerves

eg: CNIII, CN VII, CN IX, CN X, S2-S4
* *S2-S4 exit spinal levels as pelvic splanchnic nerves

Question 22

where are the cell bodies for PSNS pre-synaptic fibers?

Answer 22

brain stem and sacral spinal levels

Question 23

where are the cell bodies for the post synaptic fibers of the PSNS

Answer 23

4 specific cranial ganglia

• celiac ganglion (oculomotor n.)
• pterygopalatine ganglion, submandibular ganglion (facial n.)
• otic ganglion (glossopharyngeal n.)

or walls of target organ (intrinsic PSNS)

Question 24

what are autonomic plexuses?

Answer 24

they carry both SNS and PSNS fibers to target organs
travel on vasculature

SNS: post synaptic fibers
PSNS: presynaptic fibers