Question

Which two of the following changes (a-d) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)?
(1)Increase in red blood cell size.
(2)Increase in red blood cell production.
(3)Increased breathing rate.
(4)Increase in thrombocyte count.

• A. 1 and 2
• B. 2 and 3
• C. 3 and 4
• D. 1 and 4

Answer 1

The correct option is B 2 and 3

The most significant limiting factor in high mountain regions is the lower air pressure, which makes it more difficult for oxygen to enter our vascular systems resulting into hypoxia. When we travel to high mountain areas, our bodies initially develop inefficient physiological responses. Then there is an increase in breathing and heart rate to as much as double, even while resting. Pulse rate and blood pressure go up sharply as our hearts pump harder to get more oxygen to the cells. These are stressful changes, especially for people with weak heart. Later, a more efficient response normally develops as acclimatization takes place. Additional red blood cells and capillaries are produced to carry more oxygen. The lungs increase in size to facilitate the osmosis of oxygen and carbon dioxide. There is also an increase in the vascular network of muscles which enhances the transfer of gases.