Muscle Tissue - Quiz 2

Question 1

What do you call a synapse between a skeletal muscle cell and a motor neuron?

Answer 1

A neuromuscular junction (NMJ)

Question 2

Where are NMJs usually located?

Answer 2

the midpoint of the muscle fiber

Question 3

How many NMJ are there per muscle fiber

Answer 3

usually ONE only

Question 4

How many muscle fibers can a single axon innervate?

Answer 4

up to 3000

Question 5

What is a nerve and the fibers it innervates called?

Answer 5

a Motor Unit

Question 6

What are the steps in generating a muscle action potential?

Answer 6

1. release of acetylcholine
2. activation of acetylcholine receptors
3. production of muscle action potential
   4, termination of acetylcholine activity

Question 7

What are the steps in the Sliding Filament Theory?

Answer 7

1. action potential
   2 release of calcium ions
2. exposure of myosin binding site
3. contraction cycle
4. relaxation

Question 8

What can inhibit muscle contractions?

Answer 8

1. rigor mortis
2. curare
3. acetylcholinesterase inhibitors
4. substances affecting release of acetylcholine.

Question 9

What causes rigor mortis?

Answer 9

Insufficient ATP so myosin heads can’t detach from actin.

Question 10

What does curare do?

Answer 10

Binds to acetylcholine receptors but doesn’t create an action potential.

Question 11

What are Sevin and Sarin?

Answer 11

acetylcholinesterase inhibitors.

Question 12

What is muscle tone?

Answer 12

the firmness of a skeletal muscle in a relaxed state

Question 13

What are the 2 types of hypertonicity?

Answer 13

spasticity
rigidity

Question 14

What do skeletal muscles use ATP for?

Answer 14

contraction
active transport pumps