Muscle Contractions

What does the myosin do to the actin?

• Nothing

• Pushes on it

• Pulls on it

• Breaks it into pieces

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

____________ attaches to actin to form the cross bridge.

• Troponin

• Tropomyosin

• Myosin

• Calcium

When a muscle is in a contracted position, what is the relationship between actin filaments?

• They are on top of one another

• They are beside each other

• They are close to each other

• They are far apart from each other

Match the following:

• Muscle fibers

• Myosin

• Thick fibers

• Myofibrils

• Thin fibers

• Actin

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

• Nerve junction

• Neuromuscular junction

• Muscle junction

• Crossbridge

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)