Chapter 36, Problem 20STP

Summary Introduction

To explain:

The role of breathing oxygen while climbing a mountain to reach a higher altitude.

Introduction:

The thin walls of alveoli are richly supplied with blood vessels and form the respiratory membrane through which gaseous exchange takes place. The exchange of gases is based on the pressure difference and solubility of diffusing gases. The gases always diffuse from higher concentration to lower concentration. 

Explanation of Solution

The pressure exerted by individual gas is known as partial pressure. The process of diffusion is directly proportional to the pressure caused by the gas alone. The partial pressure of oxygen in the alveoli is high as compare to the blood capillaries resulting in the movement of oxygen from higher concentration to lower concentration i.e., from alveoli to blood. The reverse happens in the case of carbon dioxide.

At high altitude, the partial pressure of oxygen is reduced due to which the rate of diffusion also decreases. As a result, the tissues experience hypoxic conditions and one may experience mountain sickness, characterized by breathlessness, headache, dizziness, nausea, vomiting, mental fatigue, and a bluish tinge on the skin and mucus membranes.

Mountaineers carry oxygen cylinders with them to make oxygen available for their body tissues. the energy required while climbing a summit that is produced by aerobic respiration. A sufficient supply of oxygen would enable a mountaineer to complete breakdown glucose to generate energy in the form of ATP. This energy is utilized by the mountaineers for reaching higher altitudes.

Conclusion

At higher altitudes, the partial pressure of oxygen decreases due to which the gaseous exchange does not take place efficiently through the respiratory membrane along the concentration gradient. To overcome the oxygen shortage in tissues, mountaineers carry an oxygen cylinder which helps to maintain the ideal pressure conditions for the gaseous exchange.