Question

Which of the following is/are the mechanism(s) by which our body acclimatizes to the less availability of oxygen at higher altitudes?

• A. Increasing the number of erythrocytes
• B. Increasing the affinity of haemoglobin towards oxygen
• C. Decreasing the rate of breathing
• D. Both b and c

Answer 1

The correct option is A Increasing the number of erythrocytes

Adaptation or acclimatisation refers to the morphological, physiological or behavioural adjustments that allow organisms to survive in new environments or in changing conditions in their current environment.

As we move to higher altitudes, the density of gases in air decreases gradually. Due to this the availability of oxygen at higher altitudes is less. This causes people, moving to places at higher elevations, to initially experience difficulty in breathing, dizziness, etc.

The feeling however passes with time and an individual gets adapted to the atmospheric conditions of places at higher altitudes. This is due to some physiological adaptations that the body undergoes to adjust to the less availability of oxygen in the air.

• For short term relief, the rate of breathing is increased so that more oxygen can be inhaled per minute. The affinity of haemoglobin towards oxygen is also reduced to allow faster dissociation of the oxyhaemoglobin complex near the tissues so that oxygen is free to diffuse into the cells.
• A long-term adaptation is the increase in the number of red blood cells (erythrocytes) to increase the transport of available oxygen to the tissues.