LEC-7/8 Spinal Path I & II Flashcards Preview

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Flashcards in LEC-7/8 Spinal Path I & II Deck (30):
1

A group of neurons with a similar embryonic origin and function is referred to as a ___________.

Nucleus

Ex. Caudate nucleus

2

A ___________ is a group of nerve fibers in the CNS that have a similar origin and function.

Tract

Ex. Sensory - Spinothalamic tract; Motor - Corticospinal tract

3

The path of sensory information that a signal follows from receptors to the cortex is a ___________.

Pathway

4

The (medial lemniscus/spinothalamic) pathway is primarily associated with touch, vibration, and proprioception.

Medial lemniscus

5

The (medial lemniscus/spinothalamic) pathway is primarily associated with pain and temperature.

Spinothalamic

6

The fasciculus gracilis carries sensory information from the (upper/lower) body.

Lower body (below T6)

7

The fasciculus cuneatus carries sensory information from the (upper/lower) body.

Upper body (above T6)

8

The dorsal column-medial lemniscal pathway decussates at the (upper medulla/pons/lower medulla).

Lower medulla

9

Second-order neurons of the dorsal column-medial lemniscal pathway decussate as _____________ fibers.

Internal arcuate fibers

10

After internal arcuate fibers decussate at the lower medulla in the dorsal column-medial lemniscal pathway, they form the _________ on the other side of the medulla.

Medial lemniscus

11

The medial lemniscus axons terminate in the (VPL/VPM) of the thalamus.

VPL

12

Axons in the spinothalamic tract begin to decussate immediately after entering the spinal cord, passing through the ____________ in the central gray matter.

Anterior commisure

13

(T/F) Axons in the spinothalamic tract decussate immediately in the same spinal segment the sensory information originated from.

False. Axons in the spinothalamic tract begin to decussate immediately after entering the spinal cord, but it takes 2-3 spinal cord segments to accomplish this. Therefore, a lesion in the spinothalamic tract will affect contralateral pain perception beginning a few segments below the level of the lesion.

14

The corticospinal tract has neuronal origins in the ____________, ____________, and _____________.

I. Primary motor cortex (Brodmann's 4)
II. Premotor and supplementary motor areas (Brodmann's 6)
III. Primary somatosensory and parietal association cortices (Brodmann's 3,1,2,5,7)

15

Corticospinal fibers course through the (anterior limb/genu/posterior limb) of the internal capsule.

Posterior limb

16

The internal capsule is white matter present in the forebrain that separates the __________ and __________ from the __________ and __________.

-Thalamus
-Head of caudate nucleus
from the
-Putamen
-Globus pallidus

17

Corticospinal fibers course through the (substantia nigra/basis pedunculi) of the cerebral peduncles in the midbrain.

Basis pedunculi

18

About __% of corticospinal (pyramidal) tract fibers decussate in the pyramidal decussation to become the lateral corticospinal tract.

80%

19

The remaining 20% of fibers that do not decussate in the pyramidal decussation become the ________________.

Anterior (ventral) corticospinal tract

20

Lateral corticospinal fibers typically terminate on lamina __ of the spinal cord.

IX

21

Lesions in the corticospinal tract above the pyramidal decussation will elicit effects (contralaterally/ipsilaterally).

Contralaterally

22

A lesion in the motor cortex will affect motor neurons (ipsilateral/contralateral) to the lesion.

Contralateral

23

A lesion in the internal capsule will affect motor neurons (ipsilateral/contralateral) to the lesion.

Contralateral

24

A lesion in the midbrain will affect motor neurons (ipsilateral/contralateral) to the lesion.

Contralateral

25

A lesion in the pons will affect motor neurons (ipsilateral/contralateral) to the lesion.

Contralateral

26

A lesion in the medulla will affect motor neurons (ipsilateral/contralateral) to the lesion.

Contralateral

27

A lesion in the spinal cord will affect motor neurons (ipsilateral/contralateral) to the lesion.

Ipsilateral (Spinal cord is below the cervicomedullary junction and foramen magnum, which is where the pyramidal decussation occurs)

28

A lesion in (upper/lower) motor neurons causes hyper-reflexia.

Upper motor neurons

Lower motor neurons cause hypo-reflexia

29

A lesion in (upper/lower) motor neurons causes decreased muscle tone.

Lower motor neurons.

Upper motor neuron lesions cause increased muscle tone

30

(T/F) Fasciculations and muscle atrophy are typically present in upper motor neuron lesions.

False. Fasciculations and muscle atrophy are characteristic of lower motor neuron lesions.