Muscle Comparative Physiology

Question 1

What is the force in a sarcomere proportional to?

Answer 1

The amount of over lap/number of cross bridges

Question 2

What is the ‘muscle problem’?

Answer 2

A sarcomere/muscle can either be very strong (long sarcomeres) or contract fast (short sarcomeres), not both

Question 3

What are the 2 types of fibre found in muscles?

Answer 3

Slow twitch and fast twitch

Question 4

What are the characteristics of fast twitch fibres?

Answer 4

Few mitochondria and blood vessels
Fatigue quickly
Cannot replenish ATP for prolonged contraction
Good for power speed or strength

Question 5

What are the characteristics of slow twitch fibres?

Answer 5

Contains myoglobin
Many mitochondria and blood vessels
Reserves of glycogen and fat
Can recycle cross bridges rapidly 
Resistant to fatigue

Question 6

How do locusts overcome the muscle problem?

Answer 6

Storage of power in catapult, semi lunar process

Question 7

What are synchronous and asynchronous flight muscles in insects?

Answer 7

Synchronous, one contraction per spike

Asynchronous, many contractions per spike (low spike rate)

Question 8

Why do molluscs have very slow muscles?

Answer 8

Catch allows contraction to be maintained for extended periods of times (tides), requires very little energy to remain locked

Question 9

What is maximum force called?

Answer 9

Tetanus

Question 10

What leads to the tetanus

Answer 10

Accumulation of psps causing an increase in twitch (the number of motor units activated)