Section 1 corrections

Question 1

Describe the structure of a motor unit.

Answer 1

Motorone and a muscle fibres

Question 2

What is the effect of stimulating more motor units?

Answer 2

More recruitment of muscles
increased force of attraction

Question 3

Give three ways in which a warm up would affect the speed and strength of skeletal
muscle contractions.

Answer 3

increased temperature
increased muscle elasticity
increased muscle recruitment

Question 4

what is the resting HR of a trained athlete

Answer 4

50bpm

Question 5

Describe how the conduction system of the heart controls the systolic phase of the
cardiac cycle.i

Answer 5

SA node sends impulse
causing atrial systole
blood flows from atria to ventricle
AV sends impulse

Question 6

Explain why more oxygen dissociates from the blood into the muscle cell during exercise.

Answer 6

Oxygen moves from a high to low concentration
during excercise muscle uses more oxygen
increased affinity of oxygen to muscles
as there is a lower pp of 02 in muscles
diffusion gradient increases
muscles become fully saturated

Question 7

identify three mechanism of venous return

Answer 7

smooth muscles
pocket valves
skeletal pump