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Flashcards in Spinal cord & reflexes Deck (67)
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1

What fibres are present in the dorsal root?

Sensory afferent fibres

2

What fibres are present in the ventral root?

Motor efferent fibres

3

Where is the grey matter in the spinal cord?

Central

4

Where is the white matter in the spinal cord?

Peripheral

5

In which horn are motor fibres found?

Ventral horn

6

White mater is arranged in how many columns in the SC?

3 - posterior, lateral & anterior

7

What are the 3 important tracts in the SC?

Dorsal column
Corticospinal
Spinothalamic

8

What type of sensation does the spinothalamic fibres carry?

Pain & temperature

9

Where do fibres in the corticospinal tract originate?

Primary motor cortex

10

Where do lateral corticospinal fibres cross over?

Medulla (pyramids)

11

How many neurons are present in descending motor pathways?

2 - upper & lower motor neurons

12

Where is the site of the lower motor neurone?

Ventral horn

13

How many neurons are present in sensory ascending pathways?

3 - afferent sensory, medulla, thalamus

14

What type of sensation does the dorsal column carry?

Touch, vibration, pressure & proprioception

15

Where does the 2nd order neuron decussate in the ascending pathway?

Medulla

16

What is another name for the ascending sensory tracts in the brain?

Medial lemniscus

17

Where do neurons radiate from the thalamus in ascending pathways?

Post central gyrus

18

In the spinothalamic tract, where neurons cross over?

At the spinal level it enters

19

In the spinothalamic tract where does the 1st order neuronal synapse onto the 2nd order neuron?

Dorsal horn

20

What is a reflex?

An involuntary response to sensory stimuli

21

Where are reflexes mediated?

Spinal cord

22

Name a monosynaptic reflex

Stretch reflex

23

Name a polysynaptic refelx

Flexor reflex

24

In the stretch reflex, stretching of the tendon causes what?

Contraction of the agonist (quad)
Inhibition of the flexor

25

What initiates reflexes?

Painful stimuli

26

What does the flexor reflex initiate?

Flexor activity (withdrawal)
Extensor inhibition

Crossed extensor reflex - contraction of extensor on contralateral limb

27

Which neurons (UMN/LMN) mediate reflexes?

LMN

28

In an UMN lesion, what happens to reflexes?

Exaggerated

29

What happens to tone in UMN lesions?

Spasticity (hypertonicity)

30

What happens in LMN lesions?

Flaccidity (hypotoncity)