6.2 Muscular System

Multiple Choice

Which molecule is responsible for causing the conformational change in actin that activates muscle contraction?

• Ca2+

• Na+

• ATP

• Acetylcholine

Multiple Select

Which of the following statements about motor units are correct?

• A single neuron can innervate multiple muscle fibers.

• Small motor units are responsible for fine movements.

• Large motor units are responsible for gross movements.

• Each muscle fiber is innervated by multiple neurons.

Multiple Choice

What is the primary function of T-tubules in signal transduction during muscle contraction?

• Release Ca2+ into the sarcoplasm

• Transmit neurotransmitters

• Break down acetylcholine

• Generate ATP

Multiple Choice

Which type of muscle fiber is most likely to be predominant in a long distance runner?

• Type I (Slow, red)

• Type IIa (Intermediate)

• Type IIb (Fast, white)

• Type III (Unknown)

Open Ended

Explain how ATP depletion and electrolyte loss contribute to muscle fatigue during intense exercise.

Open Ended

What questions do you still have about the physiology of muscle contraction, or is there anything you would like to know more about regarding how muscles work?