Chapter 13 Part 1 Flashcards Preview

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Flashcards in Chapter 13 Part 1 Deck (42):
1

Ventral Root

Contains efferent axons, including axons that innervate skeletal muscle.

2

Dorsal Root

Contains sensory axons that connect with a single segment of the spinal cord.

3

Spinal Nerve

Contains all of the motor, sensory, and autonomic axons of a single spinal segment.

4

Dorsal root ganglion

Contains cell bodies of primary sensory neurons.

5

Tract cell

Neuron with a long axon that conveys information from the spinal cord to the brain.

6

Propriospinal neuron

Neuron that begins and ends within the spinal cord.

7

Doral ramus

Innervates paravertebral muscles, posterior vertebral structures, and overlying cutaneous areas.

8

What is a significant feature of the spinal cord?

segmental organization

9

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

by axons traveling through a pair of spinal nerves.

10

Where are spinal nerve found in the cervical region?

above the corresponding vertebrae, except the eighth spinal nerve

11

Where do spinal nerves lie in the remainder of the cord?

below the corresponding vertebrae

12

What does white matter surround?

gray matter

13

What does what matter do?

contains axons that link the cord with the brain

14

How is gray matter classified?

10 histologic regions, called Rexed’s laminae

15

What do Laminae I and II do?

process information about pain

16

What does the dorsal horn do?

processes sensory information

17

What does the lateral horn do?

processes autonomic information, and present at T1-L2 segments

18

What does the ventral horn do?

processes motor information

19

What are meninges?

layers of connective tissue that surround the spinal cord, and
are continuous with the meninges surrounding the brain

20

What is pia matter?

closely adheres to the spinal cord surface

21

What is arachnoid?

separated from the pia by cerebrospinal fluid in the subarachnoid space

22

What is dura?

tough, outer laye

23

What is the function of the spinal cord?

exchange information with brain and peripheral nerve structures and other segments

24

What do interneuronal circuits do?

integrate the activity from all sources and adjust output of lower motor neurons

25

What do interneurons do?

coordinate activity in all the muscles when a limb moves

26

What are stepping pattern generators?

Are adaptable neural networks that produce rhythmic output

27

How do stepping pattern generators work?

Contribute to stepping by activating LMNs, eliciting alternating flexion and extension at the hips and knees

28

How are stepping pattern generators activated?

when the person voluntarily sends signals from the brain to the CPGs in the spinal cord to initiate walking

29

Rexed lamina I (marginal zone)

Project neurons that receive input form small diameter afferents; once source of anteriolateral system projections

30

Rexed lamina II (substantia gelatinosa)

interneurons that receive input mainly from small diameter afferents; integrates feedforward and feeback inputs that modulate pain transmission

31

Rexed lamina III/IV (nucleus proprius)

interneurons that integrate inputs from small and large diameter afferents

32

Rexed lamina V/VI (base of dorsal horn)

projection neurons that receive input from both large and small diameter affterents and spinal interneurons; another source of anterolateral system projections

33

Rexed lamina VII (intermediate gray)

interneurons that communicate between dorsal and ventral horns; includes dorsal nucleus of Clarke

34

Rexed lamina VIII (motor interneurons)

interneurons in the medial aspect of ventral horn that coordinate the activities of lower motor neurons

35

Rexed lamina IX (motor neuron columns)

columns of lower motor neurons that govern limb musculature

36

Rezed lamina X (central gray)

interneurons surrounding the rudiment of the central cord

37

What do interneurons in inhibited circuits do?

contribute to spinal cord motor coordination

38

What do inhibitory interneurons provide:

Reciprocal inhibition
Recurrent inhibition

39

What does reciprocal inhibition do?

Decreases activity in antagonist when an agonist is active, allowing the agonist to act unoppose
separates muscles into agonists and antagonists

40

What is recurrent inhibition?

Effects opposite to reciprocal inhibition: inhibition of agonists and synergists, disinhibition of antagonists

41

What are Renshaw cells?

interneurons that produce recurrent inhibition

42

How are Renshaw cells stimulated?

by a recurrent collateral branch from the alpha motor neuron