Spinal Cord Organization Flashcards Preview

Jason's Neuro Block > Spinal Cord Organization > Flashcards

Flashcards in Spinal Cord Organization Deck (30):
1

what are segmental pattern generators?

eg. gait/walking reflex, complex patterns generated in only spinal cord

2

spinal nerve at L5 longer or shorter than at T7?

Longer

3

Where do to a lumbar puncture?

L3-4

4

more or less white matter as you go caudally? rostrally?

caudally: less white matter
rostrally: more white matter for more tracts joining up

5

nociceptors travel up which system on which side?

contralateral side
anterolateral system

6

mechanoreceptors travel up which columns?

dorsal or posterior columns

7

more ascending or descending tracts?

more descending

8

lateral descending tract is for what?

motor

9

communication within spinal cord?

yes, a lot of interneurons talk to each other

10

as you move more later in ventral roots, what is innervated?

more distal muscles

11

medial ventral horn innervated what?

proximal muscles

12

what is a motor unit

a motor neuron connected to a collection of muscle fibers: varied in numbers

13

what is an intrafusal muscle fiber?

sensory fiber embedded within muscle spindle to detect amount of muscle stretch

14

can an intrafusal muscle fiber contract?

yes to adjust their position with surrounding muscles via gamma motor neurons (not alpha like the normal ones)

15

What is the only exception where a muscle as no intrafusal muscle fiber?

extraoccular eye muscles

16

What do golgi tendon organs do?

respond to force
placed in series

17

How are intrafusal muscle fibers placed in spindle?

in parallel

18

what is the 'most important sign in neurology'?

monosynaptic stretch reflex

19

When the spindle afferent sends signal after stretch reflex, where does it go what does it do?

Goes to dorsal horn splits:
activates agonist
interneuron to antagonist: inhibites antagonist

20

is golgi organ afferent signalling monosynaptic?

Nope.

21

what is intersegmental cross-extensor reflex?

usually in cats/dogs, withdraw one limb, extend other 3 to maintain stability

22

are all interneurons short?

Nope, some really long can span multiple segments for complex reflexes

23

do lateral of medial have short or long interneurons?

medial: longer interneurons
lateral: shorter interneurons

24

spinal cord is in a usual state of?

inhibition until it's lifted to allow excitation

25

what is an upper motor neuron problem?

any neuron that affects excitability of lower motor neuron

26

what is lower motor neuron?

ventral horn of spinal cord out to periphery

27

most interneurons are excitatory or inhibitory?

inhibitory

28

if you have a lesion in a descending upper motor neuron, what happens down stream?

increased tone/clonus cause lost inhibition

29

if you have a lesion in a lower motor neuron what happens downstream?

flaccid

30

What happens to muscles affected by stroke?

increased tone, exaggerated contractions where there is little inhibition