Self-test questions: Chapter 38

. At rest, the skeletal muscles account for around half of the oxygen taken up by the body.

True

False

. In severe exercise the oxygen consumption can exceed 2 l min-1.

True

False

. The SI unit of energy or work is the joule.

True

False

. The proportion of aerobic and anaerobic metabolism is independent of the severity and duration of the exercise.

True

False

. Concerning metabolism during exercise:

Fats are the main source of energy during exercise.

The contribution made by anaerobic exercise increases during prolonged exercise.

Carbohydrates provide the main source of energy in exercise.

Plasma glucose falls significantly during a bout of heavy work lasting for 2 hours.

. Regarding circulatory adjustments during exercise:

The cardiac output increases more than tenfold in severe exercise.

The increase in cardiac output during exercise is mainly due to an increase in stroke volume.

The stroke volume increases in exercise despite a smaller end-diastolic volume.

In severe exercise the mean arterial pressure is unchanged because diastolic pressure falls.

. Which of the following are correct statements regarding the respiratory adjustments seen in exercise? Please select all that apply.

The activity of the joint receptors is an important factor driving the increase in ventilation.

During exercise the arterial PCO₂ rises significantly.

As the intensity of exercise increases the arterio-venous difference in oxygen content becomes wider.

During exercise the arterial PO₂ falls.

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