Session 11: Skeletal Muscle Metabolism - Lecture 22: Muscle Tension, Cardiac Muscle and Smooth Muscle

Question 1

True or False: 2 AP → 1 muscle AP; both the same size?

Answer 1

False.

Correct answer: 1 AP → 1 muscle AP; both the same size.

Question 2

What are the four variations that change the forces of muscle fibre contraction?

Answer 2

1. Frequency of stimulation – how often nerve impulses
   elicit muscle contraction
2. Amount of stretch before contraction
3. Nutrient and oxygen availability (oxygen debt)
4. Number of muscle fibers contracting in unison

Question 3

Motor unit =

Answer 3

1 somatic motor neuron + all the skeletal muscle cells (fibers) it stimulates (10 cells to 2,000 cells)

Question 4

One nerve cell supplies on average how many muscle cells that all contract in unison?

Answer 4

150 muscle cells.

Question 5

The total strength of a contraction depends on what?

Answer 5

Total strength of a contraction depends on how many motor units are activated & how large the motor units are.

Question 6

What is a Twitch Contraction?

Answer 6

A twitch contraction is a brief contraction of all the muscle fibers in a motor unit in response to a single action potential.

Question 7

In Myogram it has 4 parts, what are they?

Answer 7

1. Latent Period
2. Contraction Period
3. Relaxation Period
4. Refractory Period