Muscle Physiology

Question 1

What does the sliding filament model of contraction state?

Answer 1

During the contraction, the thin myofilaments slide over the thick myofilaments so that they overlap by a greater degree

Question 2

What happens to the I band, A band, Z disc, and H zone during muscle contraction?

Answer 2

A band does not change in length

I band shorten

Distance between successive Z discs decrease

H zones disappear

Question 3

What is the sequence of events for muscle contraction to take place?

Answer 3

1. Muscle fiber must be stimulated by a nerve ending so that change in membrane potential occurs
2. An action potential must occur
3. The action potential is propagated along the sarcolemma
4. Intercellular calcium ion levels must rise briefly, providing the final trigger for contraction