Deck 11: Respiration During Exercise

Question 1

The carotid bodies are chemoreceptors that are sensitive to changes in arterial a. H⁺ and K⁺ concentrations.
B) pH, PCO₂, and PO₂.
C) pH and K⁺ concentrations.
D) PO₂ only.

Answer 1

B

Question 2

The ventilatory central chemoreceptors respond to changes in the a. pH of mixed venous blood.
B) pH of cerebral spinal fluid.
C) PO₂, pH, and PCO₂ of arterial blood.
D) PCO₂ and H⁺ of mixed venous blood.

Answer 2

B

Question 3

The primary purpose of the pulmonary system is a. ventilation.
B) to provide an interface for gas exchange.
C) to transport O₂ and CO₂ in the blood.
D) formation of surfactant.

Answer 3

B

Question 4

The volume of gas that reaches the respiratory zone (gas-exchange zone) of the lung is termed a. anatomical dead space.
B) minute ventilation.
C) alveolar ventilation.
D) tidal volume.

Question 5

The term ventilation refers to the a. cooling of the airways by respiration.
B) random movement of molecules from an area of high concentration to an area of lower concentration.
C) mechanical process of moving air in and out of the lungs.
D) oxygenation of blood as it travels through the lungs.

Question 6

A decrease in arterial PO₂ below 70 mm Hg would likely result in a. a decrease in alveolar ventilation.
B) an increase in alveolar ventilation.
C) no change in alveolar ventilation.

Question 7

Exercise-induced asthma would reduce airflow by a. lowering the atmospheric pressure.
B) lowering the intrapulmonary pressure.
C) inhibiting action potentials to the diaphragm.
D) increasing airway resistance.

Question 8

Ventilation may drift upward during constant-load submaximal exercise performed in a hot and humid environment due to a. a lower arterial PO₂.
B) a higher PCO₂.
C) higher blood temperature.
D) all of the above.

Question 9

Most of the O₂ that is transported in the blood is in a. a solution as a dissolved gas.
B) the form of oxyhemoglobin.
C) the form of carboxyhemoglobin.
D) the form of deoxyhemoglobin.

Question 10

During exercise at sea level, young, healthy untrained subjects generally maintain exercise arterial PO₂ within a. 1 mm Hg of resting values.
B) 10-12 mm Hg of resting values.
C) 15-20 mm Hg of resting values.
D) 30-40 mm Hg of resting values.

Question 11

Under normal conditions, the characteristics of arterial blood include a. PO₂ of 100 mmHg.
B) oxyhemoglobin saturation of 97-98%.
C) oxygen content of 20 ml O₂ / 100 ml blood.
D) all of the above.

Question 12

The alinear rise in ventilation observed during incremental exercise (i.e., ventilatory threshold) is thought to be principally due to a. a decrease in arterial PO₂.
B) an increase in arterial PCO₂.
C an increase in arterial pH.
D) a decrease in arterial pH.

Question 13

Activation of rectus abdominis muscles would result in a. active inspiration.
B) passive inspiration.
C) active expiration.
D) passive expiration.

Question 14

In the standing position, blood flow to the base of the lung is ______________ blood flow to the apex. a. less than
B) the same as
C) greater than

Question 15

Exercise-induced hypoxemia that may occur in elite endurance athletes during heavy exercise is likely due to a. overt lung disease.
B) reduced alveolar ventilation due to exercise-induced asthma.
C) a right-to-left shunt.
D) a diffusion limitation secondary to a rapid red blood cell transit time.

Question 16

Myoglobin is a red pigment found in skeletal muscle that serves to a. transport CO₂ from the cell membrane to the mitochondria.
B) transport O₂ from the cell membrane to the mitochondria.
C) buffer changes in hydrogen ion concentration in the cell.
D) transport O₂ from the mitochondria to the cell membrane.

Question 17

Carbon dioxide is transported in the blood principally as a. carbaminohemoglobin.
B) dissolved CO₂ in solution in the blood.
C) bicarbonate.
D) carbon monoxide.

Question 18

A by-product of anaerobic glycolysis in red blood cells that is thought to alter the O₂-Hb dissociation curve is a. lactic acid
B) 2-3 DPG
C) CO₂
D) O₂

Question 19

Under normal conditions, the partial pressure of oxygen in the alveoli is a. 760 mmHg.
B) 159 mmHg.
C) 105 mmHg.
D) 100 mmHg.

Question 20

Mitochondrial PO₂ is _____________ capillary PO₂. a. greater than
B) less than
C) equal to

Question 21

In response to exercise training, the normal lung a. increases the number of alveoli.
B) does not undergo measurable changes.
C) decreases anatomical dead space.
D) increases total lung volume.

Question 22

In a pulmonary function test, a FEV₁/FVC ratio of 0.70 is a. considered normal.
B) higher than normal.
C) suggestive of airway obstruction.
D) associated with a high VO₂ max.