A thin filament

The sarcomere

A motor unit

A motor end plate

A thick filament

The length of a muscle before contraction only affects the amount of force that can be produced in tetanic contractions

The length of a muscle before contraction has no affect on the amount of force the muscle can exert when stimulated.

The length of a muscle before contraction has an important effect on the amount of force the muscle can exert when stimulated.

The length of a muscle before contraction only affects passive force when stimulated

The length of a muscle before contraction only affects active force when stimulated

3, 2, 1.

2, 1, 3.

 2, 3, 1.

1, 3, 2.

Total force peaks

Passive force peaks

Passive force is minimum

Active force is at a minimum

Active force peaks

Thick and thin filaments slide past each other

Muscle fibres shorten

Ca++ release from the sarcoplasmic reticulum is required

Muscle fibres stretch

Thick and thin filaments bind to each other