Question

Select the phrase that best describes po2 at the arterial ends of the pulmonary capillaries. the po2 is higher at first in the capillaries than in the alveoli, and then it is lower in the alveoli than in the capillaries. the po2 is lower at first in the capillaries than in the alveoli, and then it is higher in the alveoli than in the capillaries. the po2 is lower in the capillaries than in the alveoli. the po2 is higher in the capillaries than in the alveoli. the po2 is equal in the capillaries and in the alveoli.

Answer 1

the po2 is lower at first in the capillaries than in the alveoli, and then it is higher in the alveoli than in the capillaries

Answer 2

The arterial end is the part where the blood enters from the capillaries into the alveolus. The PO2 at the arterial end has a lower concentration of oxygen that is the PO2 is 40 and once this blood enters the alveolus the oxygen from the air in the alveoli dissolved in the blood hence increasing the PO2 of the air. The PO2 of the air remains the same until it reaches the body part where the oxygen is again consumed. Hence the option PO2 in the capillaries is lower than the PO2 in the alveoli is the right option