Which correctly describes the cause of the increase in alveolar ventilation that occurs when a person ascends to high altitude?
A. The decrease in PCO2 of inspired air decreases alveolar PCO2, stimulating the peripheral chemoreceptors.
B. The decrease in PCO2 of inspired air decreases alveolar PCO2, stimulating the central chemoreceptors.
C. The decrease in PO2 of inspired air decreases alveolar and arterial PO2, stimulating the peripheral chemoreceptors.
D. The decrease in total atmospheric pressure causes a greater negative pressure in the intrapleural space, resulting in deeper and more frequent breathing.
E. The decrease in the total barometric pressure at high altitude causes hypocapnea, which stimulates peripheral chemoreceptors.
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Question 2) The diaphragm is a large sheet of smooth muscle that separates the thoracic cavity from the abdomen.
Indicate whether the statement is true or false.
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Question 3) If the parietal pleura is cut during surgery, the lung on the side of the cut will expand and the chest wall will be compressed.
Indicate whether the statement is true or false.
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Question 4) The process of ventilation includes both the transport of gases by bulk flow and the diffusion of gases into and out of the blood.
Indicate whether the statement is true or false.
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Question 5) Following strenuous exercise, blood levels of lactic acid are ________ compared to pre-exercise levels. This change in acid concentration causes a reflex ________ in ventilation by activating ________.
A. decreased; decrease; peripheral chemoreceptors
B. decreased; decrease; central chemoreceptors
C. increased; increase; baroreceptors in the aortic arch
D. increased; increase; central chemoreceptors
E. increased; increase; peripheral chemoreceptors
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Question 6) Which of the following conditions would result in a systemic arterial PO2 lower than is typical of a healthy person at sea level?
A. traveling to high altitude
B. breathing 100 oxygen
C. having iron-deficiency anemia
D. breathing regular air in a hyperbaric chamber (higher that normal atmospheric pressure)
E. maintaining alveolar ventilation constant while decreasing metabolic rate
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Question 7) Which is characteristic of a person chronically suffering from hypoxic hypoxia?
A. higher-than-normal alveolar PO2
B. higher-than-normal hematocrit
C. higher-than-normal arterial PO2
D. lower-than-normal lactic acid production
E. lower-than-normal blood flow through tissues
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Question 8) Which of the following statements regarding hypoxia is correct?
A. Exposure to high altitude is a form of hypoxic hypoxia.
B. Anemic hypoxia refers to the condition of lower than normal arterial PO2.
C. Carbon monoxide poisoning is an example of hypoxic hypoxia.
D. Carbon monoxide poisoning is an example of ischemic hypoxia.
E. Cyanide poisoning is an example of hypoxic hypoxia.
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Question 9) Which of these does NOT increase during heavy exercise?
A. minute ventilation
B. arterial PCO2
C. oxygen delivery to muscles
D. oxygen extraction from the blood by muscles
E. body heat production
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Question 10) What is the primary regulator of the magnitude of alveolar ventilation under normal circumstances?
A. the H+ concentration in the brain extracellular fluid, which is monitored by central chemoreceptors
B. The PO2 of the arterial blood, which is monitored by central chemoreceptors
C. The PO2 of the arterial blood, which is monitored by peripheral chemoreceptors
D. the H+ concentration in the arterial blood, which is monitored by central chemoreceptors
E. stretch receptors in the lung
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