Peripheral Nervous System

Question 1

Where do sensory nerve originate?

Answer 1

Dorsal Root Ganglia

Question 2

Where do motor nerves originate?

Answer 2

anterior; ventral horn of the spinal cord

Question 3

Where do sympathetic nerves originate?

Answer 3

Lateral Horn of the Thoracic Spinal Cord

Question 4

Where do parasympathetic nerves originate?

Answer 4

Lateral gray mater of the sacral levels of the spinal cord and the brain itself

Question 5

What is an Axon?

Answer 5

projection of a nerve away from the cell body that conducts impulses

Question 6

What is a Dendrite?

Answer 6

an extension of the cell body that receives signals from other cells

Question 7

What is the Endoneurium?

Answer 7

The innermost covering of a peripheral nerve
- Surrounding each individual neuron

Question 8

What is the Epineurium?

Answer 8

Outermost covering of a peripheral nerve that surrounds the entire nerve.

Question 9

What is a Motor Unit?

Answer 9

A single motor neuron and all the muscle fibers it innervates

Question 10

What is Myelin Sheath?

Answer 10

Sheath that surrounds certain nerves

• works to increase conductivity of nerve impulses

Question 11

What is Nerve Conduction Velocity?

Answer 11

The speed of a nerve impulse along the axon of a nerve.

Question 12

What is a Neuron?

Answer 12

Nerve cell that receives and sends signals to other cells

Comprised of:
- Cell Body
- Axon
- Dendrites

Question 13

What are Nodes of Ranvier?

Answer 13

Brief gaps in myelination of an axon

• Serves to facilitate rapid conduction of a nerve impulse via jumping from gap node to gap node

Question 14

What is Perineurium?

Answer 14

Middle layer of covering surrounding the peripheral nerve

• Envelopes fascicles or groups of axons
• Maintains blood-nerve barrier

Question 15

What is Saltatory Conduction?

Answer 15

Action potential moving along an axon in a jumping fashion from node to node

• increases speed of conduction

Question 16

What are Schwann Cells?

Answer 16

Cells that cover the nerve fibers within the PNS and form the myelin sheath

Question 17

Which nerve layer forms the blood brain barrier?

Answer 17

Perineurium

Question 18

Which term is most synonymous with the short period of time following an action potential when sodium channels cannot be reactivated?

repolarization period
relative refractory period
depolarization period
absolute refractory period

Answer 18

absolute refractory period

Once sodium channels have closed they cannot be reopened by another action potential for a short period of time. This period is known as the absolute refractory period.

Question 19

In the central nervous system, which neurotransmitter is considered inhibitory?

norepinephrine
glutamate
gamma-aminobutyric acid
nitric oxide

Answer 19

Gamma-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system. GABA contributes to motor control, vision, and many other cortical functions.