Which of the following factors is/are responsible for muscular fatigue? (Circle all that apply.)


a. Accumulation of chemicals, including calcium and phosphate ions & increased blood flow to the muscle
b. Decreased availability of oxygen
c. Psychological and environmental factors
d. Depletion of key metabolic fuels, such as creatine phosphate

Thick filaments are composed of the protein

a. myosin.

b. actin.

c. troponin.

d. tropomyosin.

e.Choices b, c, and d are correct.

Match the following terms with the correct definition.      

____Z-disc     

____Sarcomere     

____A band     

____H zone     

____I band     

____M line

a. The dark band containing the entire length of the thick filament

b. The band of proteins in the middle of the H zone

c. The boundary between sarcomeres

d. The functional unit of contraction

e. The middle region of the A band containing only thick filaments

f. The light band containing only thin filaments

Fill in the blanks: Resistance-type activities will likely rely on_______energy sources, whereas endurance activities will probably rely on_____energy sources.

Which of the following is not likely to result from endurance training alone?

a. Increase in oxidative enzymes in the muscle fiber

b. Increased numbers of mitochondria

c. Hypertrophy of the muscle fibers

d. Increase in blood supply to the muscle fibers

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

c. Muscles that require a great deal of precise control will have large motor units.

Muscle tone is:

a. the result of voluntary shortening of the muscle.

b. the result of a small amount of involuntary activation of motor units by the nervous system.

c. abnormal—a person's muscles should be relaxed normally.

d. present only where there is damage to the nervous system.

Some athletes will consume only protein for several days before a competition, which reduces the amount of glycogen in both the muscle fibers and the liver. What effect would this have on their ability to perform activities that require short, powerful bursts of activity? How would it affect their ability to perform endurance activities?

Ms. Sanchez was in a motorcycle accident in which she lost the use of her right upper limb muscles due to significant nerve damage. However, when an electrode is inserted into her muscles, they are able to contract. Explain specifically why nerve damage caused her to lose the use of her muscles. Why can they still respond to stimulation from an electrode?