Muscle Contraction Quiz

What initiates a muscle contraction?

• A signal from the nervous system

• A signal from the digestive system

• A signal from the respiratory system

• A signal from the circulatory system

What are the two types of protein filaments in myofibrils?

• Actin and myosin

• Collagen and elastin

• Keratin and fibrin

• Tubulin and dynein

What are actin filaments anchored to?

• Z lines

• M lines

• H zones

• A bands

What is the region between two Z lines called?

• Sarcomere

• Myofibril

• Cross bridge

• Filament

What overlaps the actin filaments within a sarcomere?

• Myosin filaments

• Collagen fibers

• Elastin fibers

• Tubulin filaments

What must happen for a muscle cell to contract?

• The sarcomere must lengthen.

• The sarcomere must shorten.

• The filaments must shorten.

• The filaments must lengthen.

What do thick and thin filaments do during muscle contraction?

• They shorten.

• They lengthen.

• They slide by one another.

• They remain stationary.

What is the mechanism of contraction in muscle cells?

• Binding of actin to myosin

• Binding of myosin to actin

• Binding of actin to actin

• Binding of myosin to myosin

What forms cross-bridges that generate filament movement?

• Actin binding to actin

• Myosin binding to myosin

• Myosin binding to actin

• Actin binding to myosin

According to the sliding filament theory, what do myosin filaments use to "walk" along actin filaments?

• Protein

• Calcium

• Energy from ATP

• Oxygen