Chapter 5: Internal Anatomy of the Spinal Cord

Question 1

What is located in gray matter?

Answer 1

cell bodies of the neurons

Question 2

What is located in white matter?

Answer 2

ascending and descending axons

Question 3

What do the propriospinal axons do?

Answer 3

they interconnect different segments of the spinal cord

Question 4

Dorsal horn

Answer 4

sensory

Question 5

ventral horn

Answer 5

motor

Question 6

central canal

Answer 6

dividing pint between sensory and motor portions of the spinal cord

Question 7

Where do peripheral sensory nerves enter?

Answer 7

through the dorsal root

Question 8

What is nocioceptive information

Answer 8

noxious, painful, tissue damaging information

Question 9

amount of gray matter is greatest in what region?

Answer 9

regions that innervate the limbs

Question 10

Why do the brachial and lumbosacral enlargements have large ventral and dorsal horns?

Answer 10

they are large because of the extensive motor and sensory input from the limbs

Question 11

As you ascend rostrally through the spinal cord the amount of white matter….

Answer 11

increases because ascending tracts of axons (sensory) receive more input at rostral levels

Question 12

There is much less white matter in which areas?

Answer 12

the low sacral region of the spinal cord

Question 13

Thoracic spinal cord

Answer 13

only has medial motor nuclei to innervate trunk muscles
has smaller and less complicated dorsal horn and intermediate gray
contains the intermediolateral cell group and Clarkes nucleus

Question 14

dorsal funiculus

Answer 14

lies between the two dorsal horns and carries epicritic information to the brainstem

Question 15

lateral funiculi

Answer 15

lateral to the gray matter and between the dorsal horn and the exit of the ventral roots

Question 16

ventral funiculus

Answer 16

region of white matter between the two ventral roots

Question 17

gracile fasiculus

Answer 17

located medially it is made up of dorsal root axons entering the cord at the mid-thoracic and more caudal levels

Question 18

cuneate fasiculus

Answer 18

located laterally it is made up of axons that enter more rostrally (cervical and upper thoracic)

Question 19

Where is the anterolateral system located?

Answer 19

found anteriorly and laterally in the white matter.

This system terminates mainly in the dorsal horn

Question 20

Which side of the body carries protopathic information?

Answer 20

the axons on the OPPOSITE side carry pain and temperature information

Question 21

What is the most important descending nerve tract?

Answer 21

the lateral corticospinal tract (a.k.a pyramidal tract)

Question 22

lateral corticospinal tract is concerned with…

Answer 22

distal motor control

Question 23

anterior corticospinal tract is concerned with…

Answer 23

proximal and axial muscular movement

Question 24

Which tract is part of the lateral extrapyramidal pathway?

Answer 24

the rubrospinal tract which originates in the red nucleus of the midbrain
axons immediately cross over to the opposite side
works together with the lateral corticopsinal tract for distal arm control and movement

Question 25

What tracts make up the medial extrapyramidal pathways?

Answer 25

reticulospinal tract which arises from the reticular formation of the pons and medulla
vestibulospinal tract arises from neurons int he vestibular nuclei
Both of these tracts work with the anterior corticospinal tract

Question 26

Hypothalamo-reticulo-spinal pathway

Answer 26

descending hypothalamic control of teh inermediolateral cell column
damage to any of these descending axons above T1 can cause Horner’s syndrome

Question 27

symptoms of Horner’s syndrome

Answer 27

damaged sympathetic control of the sup. cervical ganglion
small pupil
ptosis (droopy eyelid)
absence of sweating on one side

Question 28

symptoms of a lower motor neuron lesion

Answer 28

lesion is to peripheral nerve
flaccid paralysis
decreased DTR
hyporeflexic or areflexic
fasciculatons (rippling movements)

Question 29

UMN lesion

Answer 29

damage to the brains descending motor pathways
period of spinal shock
slow disuse atrophy
hyperactive reflexes
spasticity
spastic paralysis
positive babinski response

Question 30

What happens during a period of spinal shock?

Answer 30

flaccid paraplegia is seen first

spinal reflex circuits are unresponsive but remain intact