Q. Which two of the following changes (I-IV) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)? Increase in red blood cell size. Increase in red blood cell production. Increased breathing rate. Increase in thrombocyte count. Changes occurring are

A) I and III
B) III and IV
C) I and IV
D) I and II
Explanation

When a person moves to higher altitudes, the po₂ and total atmospheric pressure decrease. Hypoxia stimulates the JG-cells of the kidney to release erythropoietin hormone, which stimulates erythropoesis in bone marrow causing polycythemia. Hypoxia will also increase breathing rate. Initially, the size of RBCs will also increase but with increase in number of RBCs, the size of RBCs becomes normal.

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.