Somatosensory

Question 1

Somatosensory is responsible for?

Answer 1

• Proprioception (DC/ML -> spinothalamic -> thalamus-> cortex
• reflexes
• motor function

Question 2

T4 and T10 dermatome

Answer 2

Nipple and belly button

Question 3

D.C./ML pathway function

Answer 3

Discriminative touch, proprioception, vibration, pressure

Question 4

Spinothalamic / anterior-lateral pathway function

Answer 4

Pain and temperature

Question 5

Which fibers carry sharp pain info?

Answer 5

Nociceptors - A delta fibers

Question 6

Which fibers carry dull pain info?

Answer 6

Nociceptors- c fibers

Question 7

First and second synapse for pain and temperature info?

Answer 7

1. Spinal trigeminal nucleus

2. (Contralaterally synapse onto) VPM nucleus on thalamus

Question 8

Dermatome with smallest receptive fields and highest density of sensory neuron innervation

Answer 8

Fingertips(C7) and lips

Question 9

Where do fibers in ascending pathway for discriminative touch decussate? What about decussate for pain?

Answer 9

Touch: medulla
Pain: midline spinal cord

Question 10

Where does somatosensory info relay in thalami nuclei?

Answer 10

Ventral posterior part of thalamus

Question 11

Dorsal columns of the spinal cord contain what information? Damage would result in loss of function on which side?

Answer 11

Discriminative touch, proprioception, vibration, and pressure
Ipsilateral damage

Question 12

Referred pain due to?

Answer 12

Convergence of signals on dorsal horn cells

Question 13

What contributes to swelling, due to assistance in degranulation of mast cells?

Answer 13

Substance P

Question 14

Cape. Like loss of pain and temperature across shoulders, with no loss of tactile sensation. Rest of body normal sensation. What condition is this most likely?

Answer 14

Syringomyelia (example central cord syndrome)- only damage dermatome