41) Muscle cells

A) actively lengthen.

B) generate compression.

C) possess a mechanism that regulates the tension amount by changing the number of contracting sarcomeres.

D) vary tension production based on the amount of sodium ions bound to actin.

E) can only contract.

42) Which statement regarding isometric contractions is true?

A) Tension rises during a contraction.

B) The skeletal muscle’s length changes.

C) The tension produced never exceeds the load.

D) Tension remains at a constant level until relaxation occurs.

E) Examples are walking and running.

43) Which type of scenario is most likely?

A) Small motor units are recruited first.

B) Large motor units are recruited first.

C) Intermediate-sized motor units are recruited first.

D) All motor units are recruited simultaneously.

E) The brain chooses motor units randomly.

44) The additional oxygen required during the recovery period to restore the normal pre-exertion levels is called the

A) oxygen debt.

B) refractory oxygen amount.

C) anaerobic oxygen threshold.

D) aerobic oxygen threshold.

E) aerobic oxygen conversion.

45) Creatine phosphate serves to

A) cause the decomposition of ATP.

B) supply energy to synthesize ATP.

C) decompose ADP.

D) synthesize ADP.

E) synthesize glucose.

46) Exhaustion of energy reserves or decline in pH due to production and dissociation of lactic acid causes

A) muscle contraction.

B) the conduction of neural information to the muscle fiber.

C) muscle relaxation.

D) muscle fatigue.

E) the striated appearance of skeletal muscle.

47) During moderate activity, which of the following is true regarding muscle metabolism?

A) The ATP produced is used to build energy reserves of ATP and glycogen.

B) Most ATP is produced through glycolysis, with lactate and hydrogen ions as byproducts.

C) Glucose and fatty acids are catabolized.

D) Mitochondrial activity provides about one-third of the ATP consumed.

E) Mitochondria are not involved.

48) Which of the following occurs when glycolysis produces pyruvate faster than it can be used by the mitochondria?

A) Pyruvate levels drop in the cytoplasm.

B) Lactic acid is produced.

C) Pyruvate is converted to sucrose.

D) Lactic acid dissociates into a water molecule and hydrogen.

E) Oxygen is produced.

49) A resting muscle generates most of its ATP by

A) conversion of creatine phosphate.

B) anaerobic respiration.

C) aerobic respiration.

D) glycolysis.

E) heat loss.

50) Glycolysis

A) is an anaerobic process.

B) is the breakdown of pyruvate to glucose.

C) acts as the only source of ATP in muscle tissue.

D) is only active during rest.

E) occurs in the nucleus.