MSS Week 3

Question 1

Explain the length-tension relationship

a) Shorter resting length
b) Longer resting length

Answer 1

a) larger overlap, myosin can’t move the actin any further, can’t shorten the muscle further more
b) smaller overlap, no cross bridge cycle form

Question 2

Define Motor Unit

Answer 2

alpha motor neuron that stimulates the muscle fibers

Question 3

Describe the periods of the muscle twitch

Answer 3

Latent Period: Excitation - Contraction coupling

Contraction Period: Cross Bridge Cycle

Relaxation: Skeletal Muscle relaxation

Question 4

Define Treppe and state the two causes

Answer 4

Definition: second stimulus happens in the middle of the relaxation period, resulting in a combination of the two contractions

1) increased levels of calcium the sarcoplasmic reticulum after the first contraction
2) Heat for muscle to contract efficiently

Question 5

Define

1) Wave Summation
2) Complete Tetanus
3) Incomplete Tetanus

Answer 5

1) Building tension on the previous tension
2) Complete Tetanus: no relaxation between stimuli
3) Incomplete Tetanus: Periods of incomplete relaxation between summated stimuli

Question 6

What is the difference between Isometric and Isotonic Muscle Contraction

Answer 6

Isometric Muscle Contraction: The muscle length stays the same but the tension increases

Isotonic Muscle Contraction: The muscle tension stays the same but the muscles shortens

Question 7

What is the difference between concentric contractions and eccentric contractions?

Answer 7

Concentric contractions: muscle shortens while doing work

Eccentric contractions: muscles lengthens during work

Question 8

Muscle Fibre Types

A) Slow Oxidative Type 1
B) Fast Oxidative-Glycolytic Type 2A
C) Fast Glycolytic fibre Type 2B

Answer 8

A) Slow Oxidative Type 1: Aerobic respiration (most myoglobin
B) Fast Oxidative-Glycolytic Type 2A: Intermediate size and anaerobic respiration
C) Fast Glycolytic Fibre Type 2B: Large size in anaerobic respiration, no myoglobin