Muscular System 2

The attachment site of a muscle that does move during muscle contraction is the

• origin

• antagonist

• insertion

• prime mover

Resistance exercises increase

• mitochondria.

• amount of muscle fibers.

• muscle fiber size.

• number of muscles.

Elasticity in muscles refers to their ability to

• respond to electrical impulses.

• resume their original shape when relaxed.

• be stretched.

• to shorten.

Which of the following is a special organelle found in muscle fibers that store oxygen?

• Hemoglobin

• Myoglobin

• Glycosome

• Mitochondria

Which of the following stores calcium inside of muscle fibers?

• T-tubules

• Sarcolemma

• Sarcomeres

• Sarcoplasmic reticulum

Put the following in order from first to last.

• ACh binds to receptors on the post-synaptic cleft

• Sodium channels close and potassium channels open so that potassium leaves the cell. The charge begins to become more negative.

• Sodium channels open, allowing for sodium to enter the muscle fiber, which begins to make the cell more positive.

• The charge dips below the resting charge and rebounds to the resting charge when potassium channels close.

• Threshold is reached and an action potential fires, continuing to make the cell more postive.

What is the role of acetylcholinesterase?

• It breaks down extra ACh that did not bind to receptors in the synaptic cleft.

• It binds to ACh receptors and stimulates muscle contractions.

• It is required to release ACh from axon terminals.

• It is released out of muscle fibers, which helps alter the charge of the cells, in order to stimulate an action potential.