Anatomy: Muscle Contraction and Fatigue

Rigor mortis occur because

• Lack of calcium ions attach to tropomyosin

• Lack of ATP to cause the myosin head to release

• Muscle stiff due to lack of heat

• Lactic acid accumulates in muscle

Which of the following refers to the muscle cell?

• Myofibril

• Myofilament

• Fascicle

• Muscle fiber

Which ion below is NOT critical to muscle contraction?

• Sodium Ion

• Calcium Ion

• Phosphorus Ion

What role does calcium play in muscle contraction?

• Covers action binding sites

• Uncovers actin binding sites

• Covers myosin binding sites

• Uncovers myosin binding sites

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 closer by the actin

• The actin is pulled closer by the myosin

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

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)

This disease can cause your muscles to stop contracting.

• Tetanus

• Botulism

• Myasthenia gravis

• Rotator cuff tear