5. Sensory and Motor Tracts

Question 1

Ascending Tracts

Answer 1

somatosensory, carries impulses to cerebral cortex and cerebellum

Question 2

Descending Tracts

Answer 2

motor, concerned with control of movement originating from cerebral cortex and brainstem

Question 3

Sensory Neurons Order

Answer 3

1st Order: delivers sensations to the CNS; cell body located in dorsal/cranial root ganglion

2nd Order: interneuron with the cell body in the spinal cord

3rd Order: transmits information from the thalamus to the cerebral cortex

Question 4

Upper/Lower Motor Neurons

Answer 4

UMN: control LMN and their activity, located in the cerebral cortex and synapse with LMN in brainstem/spinal cord

LMN: directly innervate skeletal muscle, cell bodies in grey matter of the spinal cord

Question 5

Spinal Cord Organization

Answer 5

Grey Matter: cell bodies of neurons
White Matter: axons of neurons
Dorsal Root: sensory neurons carrying info from PNS to CNS
Ventral Root: motor nerve fibers from CNS to PNS

Question 6

Brainstem Organization

Answer 6

Thalamus
Midbrain
Pons
Medulla

Question 7

Corticospinal Tract (Function)

Answer 7

concerned with control of voluntary, discrete, skilled movements, especially of those of the distal parts of the limbs

Question 8

Corticospinal Tract (Pathway)

Answer 8

-UMN in primary motor cortex
-Crus Cerebri of Midbrain
-Ventral Pons
-LMN located in the ventral horn of grey matter

Question 9

Dorsal Columns

Answer 9

func: fine touch, pressure
-Ascend within fasciculus gracilis or cuneatus
-2nd Order: nucleus gracilis of medulla oblongata
-3rd Order: nucleus in thalamus and projects to somatosensory cortex
-(gracile nucleus, cuneate nucleus, medial lemniscus, thalamus, internal capsule)

Question 10

Spinothalamic Tract

Answer 10

pain and temperature
-posterior horn of grey matter
-2nd Order: cell bodies in posterior horn, ascend through spinothalamic tracts located in lateral white matter
3rd Order: nucleus in thalamus and projects to somatosensory cortex