3.19 Spinal Region Flashcards Preview

7303 Neuroanatomy > 3.19 Spinal Region > Flashcards

Flashcards in 3.19 Spinal Region Deck (33):
1

rootlets

small groups of axons sending information to the periphery

2

ventral root

combo of ventral rootlets

3

dorsal root

- contains sensory axons bring info to the spinal cord
- enters posterolateral SC via rootlets

4

How is the SC organized?

segmentally

5

How is each segment of SC connected to a specific region of the body?

by axons traveling through a pair of spinal nerves

6

What indicates segments?

connections of nerve rootlets to exterior of the cord

7

What do spinal nerves carry?

all motor and sensory axons of a single spinal segment

8

Where are the spinal nerves in the c-spine?

above corresponding vertebrae (except 8th)

9

Where do the spinal nerves run in thoracic and lumbar spine?

below corresponding vertebrae

10

dorsal horn processes:

sensory info

11

lateral horn processes:

autonomic info

12

ventral horn processes:

motor info

13

most gray matter in SC composed of

interneurons

14

interneuron locations

- cells entirely in gray matter AND
- cells with axons that travel to different levels of the cord

15

meninges

- layers of connective tissue that surround the cord
- continuous with meninges that surround the brain

16

arachnoid mater separated from pia by

CSF in the subarachnoid space

17

What causes stretching of the lumbosacral roots?

hip flexion: produces anterior mvt of cauda equina

18

effect of extension/lateral flexion on c-spine

increased intervertebral foramen pressure at all cervical levels

19

effect of physiologic motions on vertebral canal

don't significantly change size in people with normal vertebral canals

20

What neck movement increases cervical nerve root s/s?

extension

21

afferent and descending info converge on

the same spinal interneurons

22

What acts together to produce goal-oriented movements?

- reflexes
- voluntary control

23

What do reflexes depend on?

- environmental context
- task

not hardwired

24

What does spinal circuitry provide by integrating volleys of peripheral, ascending, and descending inputs?

- modulation of sensory information
- coordination of movement patterns
- autonomic regulation

25

These circuits integrate activity from all sources and adjust output of LMN

interneuronal circuits

26

What do interneurons coordinate when a limb moves?

activity in all the muscles

27

What determines whether a single alpha motor neuron will fire?

Summation of activity at 20,000 to 50,000 synapses determines whether an alpha motor neuron will fire.

28

What is a stepping pattern generator?

adaptable neural networks that produce rhythmic output

29

How does a stepping pattern generator contribute to stepping?

activating LMNs, causing alternating flexion and extension at the hips and knees

30

Normal activation of stepping pattern generators occurs when

the person voluntarily sends signals from the brain to the stepping pattern generators (SPGs) in the spinal cord to initiate walking.

31

When walking, __________ produces different responses, depending on the phase of the gait cycle

electrical stimulation to a single point on the foot

32

stepping pattern generation

If stimulus occurs at the onset of swing phase, this activity increases

tibialis anterior activity

33

stepping pattern generation

If stimulus occurs at the end of the swing phase, this happens

- tibialis anterior activity decreases
- antagonist muscle activity increases