What is the importance of acetylcholinesterase in muscle cell contraction?

The neurotransmitter released by somatic motor neurons is:

a. Acetylcholine

b. Acetylcholinesterase

c. Norepinephrine

The ions that enter the skeletal muscle cell during the generation of an action potential are

a. Calcium ions

b. Chloride ions

c. Sodium ions

d. Potassium ions

Myoglobin has a special function in muscle tissue. It:

a. 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 except:

a. More capillaries surrounding muscle fibers

b. More mitochondria in muscle cells

c. Increased size and strength of existing muscle cells

d. More myoglobin

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

Define and draw a motor unit.

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.