Define and draw a motor unit.

Myoglobin has a special function in muscle tissue. Ita. breaks down glycogen,b. is a contractile protein,c. holds a reserve supply of oxygen in the muscle.

Aerobic exercise results in all of the following excepta. more capillaries surrounding muscle fibers,b. more mitochondria in muscle cells,c. increased size and strength of existing muscle cells,d. more myoglobin.

What is the importance of acetylcholinesterase in muscle cell contraction?

Explain what is meant by the term excitation-contraction coupling.

a. Describe the structure of a sarcomere and indicate the relationship of the sarcomere to myofilaments. b. Explain the sliding filament model of contraction using appropriately labeled diagrams of a relaxed and a contracted sarcomere.

Explain how a slight (but smooth) contraction differs from a vigorous contraction of the same muscle. Use the concepts of multiple motor unit summation.

Muscle-relaxing drugs are administered to a patient during major surgery. Which of the two chemicals described next would be a good skeletal muscle relaxant and why?• Chemical A binds to and blocks ACh receptors of muscle cells.• Chemical B floods the muscle cells' cytoplasm with Ca²⁺.