Varying Strength And Delaying Muscle Fatigue

Question 1

Motor unit recruitment

Answer 1

Size of motor units recruited
Larger for greater contraction
Smaller for less powerful

Question 2

Multiple unit summation

Answer 2

Number of units recruited / more or less
Type of muscle fibre and size determined force of contraction
All or none law

Question 3

Wave summation

Answer 3

When there is a repeated nerve impulse with no time to relax so a smooth contraction occurs
Frequency of impulses/ innervations
Waves build up without being related to produce more force
Motor unit unable to relax

Question 4

Tetanic contraction

Answer 4

Most powerful force motor unit can produce

Question 5

Spatial summation

Answer 5

When the strength of a contraction changes by altering the number and size of the muscles motor units
The addition of impulses received at different places on the neuron

Question 6

What is the all or none law?

Answer 6

Where a sequence of impulses has to be sufficient in intensity to stimulate all of the muscle fibres in a motor unit for it to contract, if insufficient then no contraction will occur

Question 7

Motor unit

Answer 7

A motor neuron and all of the muscle fibres it innervates/stimulates
Can only be made from one type of muscle fibre
Can vary in size

Question 8

What type of muscle fibre is more suitable for a larger force ?

Answer 8

Type 2 fast twitch muscle fibres

Question 9

What type of muscle fibre is more suitable for a smaller force?

Answer 9

Slow twitch muscle fibres