20.9 NS: Autonomic nervous system

Question 1

Where do autonomic pathways not originate?

Where do the SNS patwhays originate?
What about the PNS?

Answer 1

Cervical cord or lumbar enlargement

SNS: thoracolumbar

PNS: cranio-sacral

Question 2

Where do SNS postganglionic neurons lie? What do they do?

Answer 2

Paravertebral ganglia (sympathetic chain): vasoconstrictor neurons

Prevertebral ganglia: neurons innervating non-vascular smooth muscle

Question 3

What are 2 locations of preganglionic parasympathetic neurons?

Answer 3

Brainstem nuclei (Edinger-Wetphal, salivatory nuclei, dorsal motor nucleus, nucleus ambiguus)

Sacral spinal cord

Question 4

Where do sacral postganglionic neurons lie?

What type of ganglia?

Answer 4

Pelvic plexus (mixed)

Question 5

SNS vs. PNS:

Which has longer pre/post ganglionic fibres?

What NTM do they use for preganglionic n? Post?

Answer 5

PNS: longer pre

Pre: ACh

Post: SNS (NA/ACh), PNS (ACh)

Question 6

What is an axon varicosity?

Answer 6

More than one site of transmitter release per axon

Question 7

Where is the nucleus of the solitary tract (NTS)? What does it do?

Answer 7

Medulla

Receives input from visceral afferents