Muscle Contraction

What is a crossbridge?

• Where myosin binds to actin

• Where the calcium crosses into the cytoplasm

• Where calcium binds with troponin

• Where titin and myosin are connected

What does calcium do to the actin?

• Covers myosin binding sites

• Uncovers myosin binding sites

• Covers actin binding sites

• Uncovers actin binding sites

What is the name of the protein that covers the binding sites on actin?

• Myosin

• Titin

• Troponin

• Tropomyosin

What does the sarcoplasmic reticulum do?

• Stores sodium

• Stores ATP

• Releases sodium

• Stores calcium

What is the name of the place where a nerve meets a muscle fiber

• Nerve junction

• Neuromuscular junction

• Muscle junction

• Crossbridge

How does the sarcomere shorten (contract) ?

• The myosin filaments contract

• The actin filaments contract

• The myosin is pulled by the actin

• The actin is pulled by the myosin

What two chemicals are necessary for muscle contraction to occur?

• Niacin and Potassium

• Calcium and ATP

• Sodium and Potassium

• Acetylcholine and Potassium

___ and ___ are regulatory proteins bound to actin.

• Myosin and actin

• Glycogen and hemoglobin

• Calcium and oxygen

• Troponin and tropomyosin

Skeletal Muscle contraction is initiated when the ________ sends a message to the muscle cell.

• Muscle cell

• Gland

• Neuron

• None of the above

The neurotransmitter that signals muscle contraction is...

• Calcium

• Actin

• Myosin

• Ach (acetylcholine)