Q160 / 200 · NEET 2012 (Screening) · Zoology
People who have migrated from the planes to an area adjoining Rohtang Pass about six months back
- Correct answerAhave more RBCs and their haemoglobin has a lower binding affinity to $\mathrm{O}_2$
- Bare not physically fit to play games like football
- Csuffer from altitude sickness with symptoms like nausea, fatigue, etc.
- Dhave the usual RBC count but their haemoglobin has very high binding affinuty to $\mathrm{O}_2$
Solution
As a person moves up a hill the $p \mathrm{O}_2$ and total atmospheric pressure decreases. Decrease in $p \mathrm{O}_2$ due to increasing altitude, stimulates the JG-cells of kidney to secrete erythropoietin hormone, increasing the number of RBCs (polycythemia) to compensate the supply of $\mathrm{O}_2$. At higher altitude, haemoglobin has lower binding affinity to $\mathrm{O}_2$ because the primary factor responsible for binding is $p_2$, which decreases at higher altitude.
Hence, the correct answer is option: 'A'.