Respiratory System
If the partial pressure of oxygen in alveolar air is 100 mmHg and the concentration of dissolved oxygen in capillary blood arriving at the alveoli is 40 mmHg, what will be the concentration of dissolved oxygen in blood leaving the alveoli?
140 mmHg
100 mmHg
70 mmHg
60 mmHg
100 mmHg
Oxygen in alveolar air will diffuse down its concentration gradient into capillary blood until blood in the capillary is also at 100 mmHg. After this there is no concentration gradient to effect a net diffusion.
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B. The tubes that open from the left and right primary bronchi
C. The tubes that enter a lobule
D. The tubes that enter an alveolar sac
Blood entering the capillaries of the alveoli has dissolved CO2 at 46 mm Hg and is separated from air in the alveoli, which contains CO2 at a partial pressure of 40 mm Hg, by the respiratory membrane. What will be the concentration of dissolved CO2 of the blood capillaries leaving the alveoli?
A. 40 mm Hg
B. 43 mm Hg
C. 46 mm Hg
D. 86 mm Hg
Mt. Everest “base camp” is located 5300 m above sea level. Here, the atmospheric pressure is 403 mmHg (rather than 760 mmHg at sea level), and the oxygen partial pressure in atmospheric air at this altitude is about 79 mmHg. What is the likely value for dissolved oxygen concentration in arterial blood for someone at base camp?
A. 149 mmHg
B. 104 mmHg
C. 79 mmHg
D. 50 mmHg
Which of the following buffer systems of the body is affected by the action of the lungs?
A. Protein
B. Monohydrogen phosphate/dihydrogen phosphate
C. Ammonia/ammonium
D. Carbonic acid/bicarbonate
Which molecule or ion dissolved in blood is able to stimulate the central chemoreceptors of the brain’s respiratory centre?
A. CO2
B. H3O+
C. O2
D. Ca2+
Which of the following lists the components of the respiratory membrane?
A. Alveolar epithelial cells, capillary endothelial cells and their basement membranes
B. Fluid and surfactant alveolar epithelial cells, capillary endothelial cells and their basement membranes
C. Visceral pleura, parietal pleura and serous fluid
D. Ciliated epithelial cells, mucus cells and secreted mucus
If the partial pressure of oxygen in the air contained in the alveoli of the lungs is 14 kPa, then the partial pressure of oxygen dissolved in the alveolar fluid will be:
A. Very close to 14 kPa
B. Significantly greater than 14 kPa
C. Significantly less than 14 kPa
D. Unable to be determined without the solubility coefficient of oxygen and the temperature of the alveolar fluid
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