Oxygen makes up 21% of air in the atmosphere. However, oxygen makes up only abou

Question

Oxygen makes up 21% of air in the atmosphere. However, oxygen makes up only about 14% of the air in the alveolar spaces of the human lung. This is because lungs do not completely collapse with each exhalation, and incoming fresh air is always mixed with air that has already undertaken some gas exchange.

1) Given that total atmospheric pressure is 760 mm Hg at sea level, what is the partial pressure of O2 (i.e., PO2) at sea level?    

2) What is PO2 in the alveoli of the human lung at sea level?    

3) Given that gas pressure between air and water (i.e., surfactant and eventually blood plasma) will come into equilibrium, what is PO2 in venuoles leaving the lungs at sea level? (Hint: Because alveoli continue to be ventilated, PO2 in alveoli will not drop as O2 is loaded into blood plasma.)  

Helpful Equations: Where R = rate of diffusion, D = constant for a gas, A = area of contact, a2-a1 = gradient, and T = thickness (diffusion distance)

Explanation / Answer

a . partial pressure of oxygen at sea level is 760 * 0.21 = 159 mm of Hg ..

b. alveolar oxygen partial pressure is lower than atmospheric oxygen partial pressure , partial pressure of water vapour reduces the oxygen partial pressure to 150 mm of Hg.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.