The nerve stimulus and action potential

Question 1

Motor unit

Answer 1

One neuron and all the skeletal muscle fibers it stimulates

Question 2

Axon

Answer 2

Thread-like extension of a neuron

Question 3

Axon terminals

Answer 3

Branches at the end of an axon

Question 4

How does contraction occur?

Answer 4

Skeletal muscle fibers stimulated by nerve impulses

Question 5

Neuromuscular junctions

Answer 5

Region where motor neuron comes into close contact with a skeletal muscle cell

Question 6

What is the neurotransmitter that stimulates skeletal muscle fibers?

Answer 6

Acetylcholine

Question 7

What is the gap between the nerve and muscle fiber?

Answer 7

Synaptic cleft

Question 8

What is step 1 of when a nerve impulse reaches the axon terminal (action potential)?

Answer 8

Calcium channels open, and calcium enters

Question 9

What is step 2 of when a nerve impulse reaches the axon terminal (action potential)?

Answer 9

Calcium entry causes the vesicles to fuse with the cell membrane and release acetylcholine

Question 10

What is step 3 of when a nerve impulse reaches the axon terminal (action potential)?

Answer 10

ACh diffuses across the synaptic cleft and attaches to the membrane receptors on the sarcolemma

Question 11

What is step 4 of when a nerve impulse reaches the axon terminal (action potential)?

Answer 11

Sodium ions now rush to muscle fiber and potassium ions diffuse out (depolarization) and more Na+ channels open

Question 12

What is step 5 of when a nerve impulse reaches the axon terminal (action potential)?

Answer 12

Movement of ions generates an action potential

Question 13

What is step 6 of when a nerve impulse reaches the axon terminal (action potential)?

Answer 13

Muscle fiber relaxes until stimulated again

Question 14

Axon hillock

Answer 14

A transition between the cell body and the start of the axon

Question 15

Cell body

Answer 15

Contains the nucleus

Question 16

Dendrite

Answer 16

Transmits and receives signals from other neurons

Question 17

Multiple sclerosis

Answer 17

A disease in which the immune system eats away at the protective covering of neves

Question 18

Myelin

Answer 18

An insulating layer that allows electrical impulses to transmit quickly and effiently along the nerve cells

Question 19

Neurotransmitter

Answer 19

Chemical messengers that allow our body to function

Question 20

Nissl bodies/substance

Answer 20

Granules in the cytoplasm made up of polyribosomes and rough ER

Question 21

Node of Ranvier

Answer 21

Wraps around axons to form myelin sheath

Question 22

Synaptic cleft/synapse

Answer 22

The space after the axon terminal between the next target cell