Chapter 12, Problem 3RQ

What is the function of the sarcoplasmic reticulum in muscle cell contraction?

In the diagram below, label the fine structure of a muscle, down to one of its myofibrils. Identify the basic unit of contraction in a myofibril.

What causes the striated appearance of skeletal muscle tissue?

What are the functional zones of a motor neuron?

What is a motor unit? Why does a rapid series of muscle twitches yield a stronger overall contraction than a single twitch?

Figure 38.37 Which of the following statements about muscle contraction is true? The power stroke occurs when ATP is hydrolyzed to ADP and phosphate. The power stroke occurs when ADP and phosphate dissociate from the myosin head. The power stroke occurs when ADP and phosphate dissociate from the actin active site. The power stroke occurs when Ca2+ binds the calcium head.

Define an action potential.

Every skeletal muscle fiber is supplied by a motor neuron at the NMJ. Watch this video (http://openstaxcollege.org/l/skelmuscfiber) to learn more about what happens at the neuromuscular junction. (a) What is the definition of a motor unit? (b) What is the structural and functional difference between a large motor unit and a small motor unit? Can you give an example of each? (c) Why is the neurotransmitter acetylcholine degraded after binding to its receptor?

In which direction would an MRI scanner move to produce sequential images of the body in the frontal plane, and in which direction would an MRI scanner move to produce sequential images of the body in the sagittal plane?