Question

6. Which of the following statements are accurate?

A. In an average, healthy human, the partial pressure of carbon dioxide is usually higher in the blood in systemic veins than the alveoli

B. In an average, healthy human, the partial pressure of oxygen is usually higher in the systemic veins than the alveoli

C. In average, healthy human, the partial pressure of oxygen is usually higher in the systemic arteries than in the body tissues

D. Generally speaking, gases will diffuse down their pressure gradient

E. In an average, healthy human, the partial pressure of carbon dioxide is usually higher in the body tissues than the systemic arteries.

7. Which of the following statements are accurate?

A. Humans bring air into their lungs by generating a positive pressure (higher pressure relative to the atmosphere)

B. When the diaphragm contracts it becomes dome-shaped and causes the lung to decrease in volume which decreases the pressure of air in the lungs.

C. In a close chamber (such as the lungs), As the volume of a gas increases the pressure decreases

D. The diaphragm is the primary breathing muscles in humans

E. In human lungs, new air mixes with air in the lungs already. This decreases the efficiency of ventilation

Answer 1

6. a) It is correct as the partial pressure of CO₂ in systemic veins is 45 mm Hg while in alveoli is 40 mm Hg because of which it is diffused out in alveoli from blood vessels.

b) It is incorrect statement as the partial pressure of oxygen in systemic veins is 40 mm Hg while in alveoli is 104 mm Hg.

c) It is correct as partial pressure of oxygen in tissue is 40 mm of Hg while that of systemic arteries is 95 mm Hg which helps to transport oxygen easily to cells.

d) Correct. Gases diffuse from region of higher pressure to a region of lower pressure.

e) Correct. Partial pressure of CO₂ in systemic arteries is 40 mm Hg while in body tissues is 45 mm Hg. As body cells produce carbon dioxide as the product of metabolism to be released out.

7. a) Incorrect. Humans will develop low pressure in lungs so that air can move from higher pressure to lower pressure region.

b) Incorrect. Diaphragm becomes flat on contraction and dome in relaxed state.

c) Correct. With increase in volume gaseous pressure decreases as more volume provides more space for gas molecules to move creating less pressure.

d) Correct. As diaphragm helps to increase thoracic cavity volume because of which pressure inside lungs lower and air diffuse inside.

e) Incorrect. Residual volumes allows continuous exchange of gases in alveoli or lungs.