What is the primary function of alveoli in the lungs?

• A. To filter out dust and pathogens from inhaled air
• B. To regulate the temperature of inhaled air
• C. To facilitate the exchange of oxygen and carbon dioxide between the air and blood
• D. To produce mucus that traps foreign particles

Answer: (C)

Verified step by step guidance

1. Understand the structure of alveoli: Alveoli are tiny air sacs located at the end of bronchioles in the lungs. They are surrounded by a network of capillaries.
2. Recognize the role of alveoli in gas exchange: The primary function of alveoli is to facilitate the exchange of gases, specifically oxygen and carbon dioxide, between the air and the blood.
3. Identify the process of gas exchange: Oxygen from inhaled air diffuses through the walls of the alveoli into the blood in the capillaries, while carbon dioxide from the blood diffuses into the alveoli to be exhaled.
4. Consider the structure-function relationship: The thin walls of the alveoli and their large surface area are crucial for efficient gas exchange, allowing for rapid diffusion of gases.
5. Clarify misconceptions: While alveoli do not filter dust or pathogens, regulate temperature, or produce mucus, these functions are performed by other parts of the respiratory system, such as the nasal passages and bronchi.