Question

Why gas exchange in the alveolar region is very rapid?

Accepted Answer

The alveoli comprise the basic structural and functional unit of the respiratory system in humans. They are lined by simple squamous epithelium that comprises a single layer of epithelial cells. Being thin, single, and moist, this surface allows easy exchange of gases through diffusion.

The diffusion of gases takes place from higher partial pressure (pp) to lower partial pressure until equilibrium is achieved between two regions. The gaseous exchange will be rapid when the difference in the pp is more. The pp of CO₂in blood entering the pulmonary capillaries is 45 mmHg while the pp of CO₂ in alveolar air is 40 mmHg and due to this difference, CO₂ diffuses into the alveoli from the capillaries. Similarly, the pp of oxygen in the blood of pulmonary capillaries is 40 mmHg and 104 mmHg in alveolar blood, this difference makes the diffusion of oxygen from alveoli to capillaries.

Maharashtra Board Solutions for Chapter: Respiration and Circulation, Exercise 8: Use Your brain Power

Maharashtra Board Biology Solutions for Exercise - Maharashtra Board Solutions for Chapter: Respiration and Circulation, Exercise 8: Use Your brain Power

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