Topic 4: Muscles

Which of these events must occur first to trigger the skeletal muscle to generate an action potential and contract?

Acetylcholine (ACh) binds to receptors on the sarcolemma and allows passage of sodium ions into the cell.

Why are calcium ions necessary for skeletal muscle contraction?

Calcium ions trigger the binding of myosin heads to actin filaments.

The epimysium is represented by ________.

Label A

The I band within a skeletal muscle fiber is indicated by ________.

Label B

What is released by axon terminals into the synaptic cleft to stimulate a muscle to contract?

acetylcholine

What is covered by the endomysium?

an individual muscle cell

striated involuntary muscle tissue is classified as _________ muscle

cardiac

Muscle tissue has the ability to shorten when adequately stimulated, a characteristic known as ________

contractility

Contractions in which muscles shorten and produce movement are known as ________

isotonic contractions

The point of muscle attachment to an immovable or less movable bone is known as the ________.

origin

Which of the following is an example of an isometric contraction?

pushing against an immovable wall

The condition of skeletal muscle fatigue can be best explained by _______

the inability of the muscle to contract even if it is being stimulated

Jason injured his hamstring muscle group during football practice. He will be unable to perform ________.

thigh extension and knee flexion

Which type of muscle tissue contracts most quickly upon stimulation?

skeletal

The type of muscle tissue pictured is __________

smooth