Question

If lung disease results in an arterial PO2 of 80 mm Hg, the ability of the blood to carry O2 to the tissues is severely compromised.

a-true
b-false

Answer 1

The claim that an arterial PO2 of 80 mm Hg significantly impacts the blood's oxygen-carrying capacity is false, as haemoglobin can still effectively transport oxygen at this pressure.

Step-by-step explanation:

The statement that an arterial PO2 of 80 mm Hg severely compromises the blood's ability to carry O2 to the tissues is false. Normally, alveolar PO2 (PALVO2) is around 100 mm Hg, and this gradient allows oxygen diffusion from the alveoli into the capillaries where it binds haemoglobin in red blood cells. However, even at a slightly reduced PO2 of 80 mm Hg, haemoglobin can still be quite saturated with oxygen, and the blood would continue to transport oxygen effectively to the tissues. The body has compensatory mechanisms, such as altered haemoglobin affinity for oxygen and autoregulation of blood flow to optimize oxygen delivery even under conditions of lower arterial PO2.