Neurophysiology

Question 1

Where do preganglionic sympathetic neurons originate?

Answer 1

nuclei of the thoracic and lumbar SC segments T1-L3

Question 2

Do sympathetic preganglionic neurons have short or long axons and why?

Answer 2

Preganglionic axons are short and postganglionic are long bc postganglionic are going out to the body

Question 3

Where do preganglionic parasympathetic neurons originate?

Answer 3

nuclei of CN 3, 7, 9, 10 or from sacral SC segments S2-S4

Question 4

Do parasympathetic preganglionic neurons have short or long axons and why?

Answer 4

Preganglionic axons are long and postganglionic are short bc postganglionic axons are near the organs but preganglionic have further to travel

Question 5

What is postural hypotension?

Answer 5

When going from supine to upright position:

–> BP decreases, lightheaded, etc. until vestibular and sympathetic NS can reach equilibrium

Question 6

Autonomic Dysreflexia

Answer 6

• Overactive sympathetic response due to innocuous stimulation
• higher risk with SCI above T5

Question 7

What spinal nerves are part of the cervical plexus?

Answer 7

C1-C4

Question 8

What spinal nerves are part of the lumbosacral plexus?

Answer 8

L1-S4

Question 9

How many nerve roots make up the sensory somatic NS?

Answer 9

• 12 CN

- 31 spinal nerves (8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal)