NS 5 - ascending tract

Question 1

how many pairs of spinal nerves are there?

Answer 1

31

Question 2

is the spinal cord shorter than the spinal canal?

Answer 2

yes

Question 3

what type of neurons project their axons into the periphery to innervate skeletal and smooth muscles that mediate voluntary and involuntary reflex?

Answer 3

motor neurones

Question 4

where are motor neurons located?

Answer 4

ventral horn

Question 5

what can cause motor and sensory abnormalities?

Answer 5

lesions in different parts of the spinal cord

Question 6

what defines a spinal segment?

Answer 6

dorsal roots entering and ventral roots exiting the cord

Question 7

define dermatome

Answer 7

an area of skin supplied by peripheral nerve fibres originating from dorsal root ganglion

Question 8

can there be overlap between neighboring dermatomes?

Answer 8

yes

Question 9

how are peripheral nerves formed?

Answer 9

ventral axon root joins with peripheral processes of the dorsal root ganglion cells to form mixed afferent and efferent spinal nerves

Question 10

describe what the transverse section of the adult spinal cord looks like?

Answer 10

white matter in the periphery, gray matter inside and a tiny central canal filled with CSF at its centre

Question 11

what surrounds the canal in a transverse section of the adult spinal cord?

Answer 11

the ependymal layer

Question 12

what type of nuclei is present in the dorsal horn?

Answer 12

sensory

Question 13

what are the three main categories of neurons found in spinal gray matter?

Answer 13

motor cells of ventral horn

tract cells and interneurons

Question 14

does white matter increase or decrease going up the tract?

Answer 14

increase

Question 15

name the three columns present in white matter

Answer 15

dorsal columns - sensory
lateral column - mixed
ventral column - mixed

Question 16

what can be sampled by inserting a needle into the subarachnoid space below the level of the conus medullaris?

Answer 16

CSF

Question 17

how many arteries supply the cord?

Answer 17

three major longitudinal arteries

• one anterior and two posterior that originate from vertebral arteries
• radicular arteries that travel along the dorsal and ventral roots

Question 18

what causes a spinal cord infarction

Answer 18

embolic occlusion

Question 19

what happens at the white commissure?

Answer 19

crossing of neurons

Question 20

where would you puncture the needle for a spinal tap?

Answer 20

L4/5

Question 21

which senses are provided by the dorsal column pathway?

Answer 21

• two point discrimination/ fine touch, vibration and conscious position sense