Which of these statements does NOT describe the plateau portion of the O₂-Hb curve
A)It is within the blood PO₂ range that exists at the pulmonary capillaries.
B)It means that haemoglobin becomes almost nearly saturated in the lungs, unless the pulmonary capillary PO₂ falls below 60 mmHg.
C)It is within the blood PO₂ range that exists at the systemic capillaries.
D)It is the range that exists at the pulmonary capillaries.

Question

Quizplus · Accepted Answer

The plateau portion of the O₂-Hb curve is not within the blood PO₂ range that exists at the systemic capillaries. It is actually the range that exists at the pulmonary capillaries where the oxygen is loaded onto haemoglobin, and it describes how saturation remains almost constant despite changes in PO₂ within this range. Option A and D both correctly describe the plateau portion, while option B is also correct, as it indicates that unless the PO₂ falls below a certain level, haemoglobin will remain almost completely saturated with oxygen.

Which of These Statements Does NOT Describe the Plateau Portion