3 Spinal Cord Tracts & Somatosensory Systems

Question 1

Describe Spinospinal tract (propriospinal system) and function

Answer 1

Axons originate and terminate in spinal cord; ascend & decend to link diff SC segments;
Role in patterns and reflexes

Question 2

Describe Spinocerebellar tract and function

Answer 2

Connect spinal cord and cerebellum;
Convey touch, pressure, and proprioceptive info for cerebellum to correct movement

Question 3

6 components of somatosensory system

Answer 3

1. Receptors
2. Primary afferent neurons (1st)
3. Prethalamic relay (2nd)
4. Decussations
5. Thalamic relay (3rd)
6. Cerebral cortex

Question 4

Spinal n C4 is between which 2 spinal segment?

Answer 4

C3-C4 (above respective vertebra)

Question 5

Spinal n C8 is between which 2 spinal segment?

Answer 5

C8-T1 (above respective vertebra)

Question 6

Spinal n T2 is between which 2 spinal segment?

Answer 6

T4-T5 (below respective vertebra)

Question 7

What alpha & gamma motor neuron innervate?

Answer 7

alpha = muscle contract
gamma = muscle spindle contract

Question 8

Explain 2 point discrimination

Answer 8

If two points on different receptive field, 2 sensations;
If two points on same receptive field, 1 sensation;
Smaller receptive fields = Better 2 point discrimination

Question 9

Explain Brown-Séquard syndrome

Answer 9

Damage to ipsilateral spinal cord;
If L damaged,

STT L input ✓, R input X
DCML L input X, R input ✓

Question 10

Explain Anterior Cord syndrome

Answer 10

STT pathway affected -> Loss of nocieception, temp sensation
CST pathway affected -> paralysis below spinal cord lvl