Chapter 6: The Sensory System

Question 1

First-order neurons are

Answer 1

The Peripheral or cranial nerves

Question 2

Pain and temperature carried by what kinds of nerves

Answer 2

A-delta (thinly myelinated)
C fibers (unmyelinated)
Slow conducting in general
Synapse in dorsal root ganglion onto second order neurons which cross
Travel in Spinothalamic Tract (anterolateral)

Question 3

Proprioception, vibration and light touch

Answer 3

Ipsilateral traveling
Heavily myelinated fivers (A-alpha, A-beta)
Second order neuron in medulla in the nuclei gracilis and cuneatus
Axons cross at lower medulla to form medial lemniscus
Dorsal Columns

Question 4

Medial/Lateral localization of nerves in Dorsal Columns and STT

Answer 4

Dorsal Columns: Medial is more distal (legs are more medial than arms)
Spinothalamic Tract: Medial is more proximal (because they cross!)

Question 5

What innervates the upper neck and the back of the head

Answer 5

C2

Question 6

What innervates the mid/lower neck

Answer 6

C3

Question 7

Memorize the dermatome Map

Answer 7

??

Question 8

Syrinx deficits

Answer 8

STT compromised early
Dorsal columns preserved
Central cord syndrome

Question 9

Negative sensory dysfunction vs. positive

Answer 9

Negative (numbness, loss of temp. sensation, blindness, deafness)
Positive (pain, paresthesias, visual sparkles, tinnitus)

Question 10

Spinal Cord Disease finding

Answer 10

Loss of function (motor or sensory) below the lesion.

Look for this when you find something like that on exam.

Question 11

Brainstem lesions

Answer 11

Ipsilateral face, contralateral body

Crossed sensory loss

Question 12

Thalamus/Cortex lesions

Answer 12

Contralateral face, arm, and leg

Question 13

Lacunar stroke

Answer 13

Thalamus or posterior limb of internal capsule (for sensory, at east)