Humans are not able to survive for long periods at very high altitudes primarily because:
1. The oxygen content is very low with respect of that found at sea level.
2. The carbon dioxide is much more than that found at sea level.
3. The partial pressure of oxygen is very low than that found at sea level.
4. The atmospheric pressure is much higher than that found at sea level, which makes the amount of oxygen available one-fourth that found at sea level.

Subtopic:  Respiratory System: Exchange of Gases |
 59%

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All the following statements regarding hemoglobin are true except:
1. Hemoglobin loads up with oxygen in the alveolar capillaries.
2. Approximately 97% of hemoglobin in red blood cells is in the form of oxyhemoglobin.
3. Hemoglobin has a lower affinity for oxygen at higher temperatures.
4. Each molecule of hemoglobin can carry one molecule of oxygen.

Subtopic:  Respiratory System: Transport of Gases |
 80%

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When you hold your breath the urge to inhale first results from
1. rising PCO2
2. falling PCO2
3. rising PO2
4. falling PO2

Subtopic:  Respiratory System: Transport of Gases Part 1 |
 72%

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The conversion of carbon dioxide into carbonic acid in the red blood cells is catalyzed by the enzyme:

1. hemoglobin 2. carbonic anhydrase
3. carbonic oxidoreductase 4. carbonic transferase
Subtopic:  Respiratory System: Exchange of Gases |
 86%
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The efficiency of a respiratory system is enhanced by all the following except:
1. increasing the surface area available for diffusion of gases
2. decreasing the distance over which the gases must diffuse
3. increasing the concentration differences of gases inside and outside the system
4. drying the system out so the gases do not have to diffuse through water

Subtopic:  Respiratory System: Exchange of Gases |
 71%

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The most efficient respiratory system amongst the following would be:
1. mammal lungs
2. reptile lungs
3. bird lungs
4. fish gills

Subtopic:  Respiratory System: Trachea & Basic Anatomy of Lung |

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The Bohr effect is a physiological phenomenon first described in 1904 by the Danish physiologist Christian Bohr. It explains why
1. hemoglobin binds carbon monoxide more readily than oxygen
2. hemoglobin unloads its oxygen when it encounters low pH
3. diffusion occurs so slowly over long distances
4. oxygen is present in the atmosphere in relatively low concentrations

Subtopic:  Respiratory System: Transport of Gases Part 2 |
 65%

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The division of the circulatory system involved in the exchange of gases between interstitial fluid and the blood are:
1. arteries
2. arterioles
3. capillaries
4. venules

Subtopic:  Respiratory System: Exchange of Gases |
 73%

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Dyspnea in an asthmatic patient is due to the constriction of the
1. trachea.
2. larynx.
3. terminal bronchioles.
4. alveoli.

Subtopic:  Respiratory Disorders: Part 1 |
 57%

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Which of the following is most likely to take place during quiet expiration?
1. abdominal muscles relax.
2. diaphragm moves inferiorly.
3. external intercostal muscles contract.
4. thorax and lungs passively recoil.

Subtopic:  Respiratory System: Pulmonary Ventilation |

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