HUMAN PHYSIOLOGY
BREATHING AND RESPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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True:This is what creates the concentration gradient
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True:This is because air flows from areas of high pressure to low pressure
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False:When exhalation occurs the air pressure decreases
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False:When you inhale you decrease the air pressure
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Detailed explanation-1: -When the lungs exhale, the diaphragm relaxes, and the volume of the thoracic cavity decreases, while the pressure within it increases. As a result, the lungs contract and air is forced out.
Detailed explanation-2: -The partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood. In contrast, the partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli.
Detailed explanation-3: -Answer. As the volume of the lungs shrinks during exhalation, the pressure in the lungs increases above that of atmospheric pressure and air moves out of the lungs down the pressure gradient.
Detailed explanation-4: -At sea level without supplemented inspired oxygenation, the alveolar oxygen partial pressure (PAO2) is: PAO2 = (760-47) 0.21-40 / 0.8 = 99.7 mm Hg.