Spinal Nerves and the Spinal Cord

Question 1

What makes up the entire PNS?

Answer 1

Spinal Nerves

Question 2

What is an endoneurium?

Answer 2

Loose, connective tissue surrounding a single axon, insulating and keeping info within that one axon

Question 3

What is a bundle of axons collected in one group in a nerve called?

Answer 3

A fascicle

Question 4

Which connective tissue layer wraps around a fascicle?

Answer 4

Perineurium

Question 5

Which connective tissue layer surround the outside of the entire nerve?

Answer 5

Epineurium

Question 6

If a nerve, an area of axons, is known as a ‘nerve’ in the Peripheral Nervous System, what is it known as in the Central Nervous System?

Answer 6

Tract, or white matter

Question 7

If ganglia, a structure containing nerve cell bodies, is known as ‘ganglia’ in the Peripheral Nervous System, what is it known as in the Central Nervous System?

Answer 7

Nuclei or grey matter

Question 8

Can axons be regenerated in the PNS?

Answer 8

It is possible but does not always. It tries to repair axons.

Question 9

Can axons be regenerated in the CNS?

Answer 9

No, because there is no mechanism in it to do so

Question 10

During the regeneration of an axon in the PNS, which side of the damaged nerve is more active in guiding the process of regeneration?

Answer 10

The side that is distal or attached to the muscle.

Question 11

During the regeneration of axon in the PNS, what is the role of the neurolymmocytes?

Answer 11

From the distal side, the neurolymmocytes divide and spread back to the proximal side. They form a channel to guid the original axon back to the effector organ.

Question 12

What causes the atrophy of a muscle?

Answer 12

If the axon is too far away from the neurolymmocytes trying to form a channel back to the axon.

Question 13

3 Functions of the Spinal Cord:

Answer 13

1) Convey sensory information from the PNS to the brain
2) Convey motor information from the brain to the PNS
3) Processes sensory information but in a limited manner

Question 14

Where is the spinal cord located in the spine?

Answer 14

In the vertebral column of the backbone.

Question 15

How many pairs of spinal nerves are there?

Answer 15

31

Question 16

What are the bundle of spinal nerves that extend beyond the spinal cord?

Answer 16

Cauda Equina

Question 17

Where does the spinal cord end?

Answer 17

Between L3 and L4.

Question 18

What are the spinal nerves grouped and categorized under?

Answer 18

Plexi (Singular: Plexus)

Question 19

Where is the cerebrospinal fluid located?

Answer 19

In the central canal of the spinal cord

Question 20

What is the role of the white matter in the spinal cord in reference to the brain?

Answer 20

It brings information to and from the brain.

Question 21

What is in the dorsal root ganglion?

Answer 21

Sensory cell bodies. It is responsible for info coming into the spinal cord.

Question 22

True or False: Spinal NERVES are mixed nerves, so info can travel right and left in the spinal cord.

Answer 22

True

Question 23

Which root does information come INTO the spinal cord, and why?

Answer 23

The Dorsal Root, and because of the Dorsal Root Ganglion which is sensory.

Question 24

5 components of a Spinal Reflux:

Answer 24

1) Sensory Receptor
2) Sensory Neuron
3) Association Neuron (although sometimes a reflux will skip the interneuron and go straight to the motor neuron)
4) Motorneuron (passes onto the spinal nerve)
5) effector organ

Question 25

Is the brain involved in the reflux process?

Answer 25

No

Question 26

3 Major Types of Spinal Reflexes:

Answer 26

1) Monosynaptic Reflex
2) Polysynaptic Reflex
3) Complex Reflex
Determined by the number of synapses between the sensory and motor neurons.

Question 27

Monosynaptic Reflex:

Answer 27

Two neurons involved, but one synapse.

Knee-jerk reflex.

Question 28

Polysynaptic Reflex:

Answer 28

Greater than two neurons are involved.
Golgi-tendon reflux.
Withdrawal reflex.

Question 29

Complex Reflex:

Answer 29

More than one effector organ is involved, like both legs.

Crossed Extensor Reflex.