What role do alveoli play in the respiratory system?

Alveoli are essential components of the respiratory system, specifically designed to facilitate gas exchange between the lungs and the bloodstream. These tiny, balloon-like structures are located at the ends of the bronchioles and are surrounded by a network of capillaries. This anatomical arrangement allows for efficient diffusion of oxygen from the alveoli into the blood while carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled.

The large surface area provided by the many alveoli, combined with their thin walls, maximizes the efficiency of this gas exchange process. The presence of surfactant within the alveoli reduces surface tension, preventing the alveoli from collapsing and ensuring that they remain functional and ready for gas exchange. This is why their primary role is critical for maintaining the body's oxygen levels and removing carbon dioxide, making them fundamental to respiratory function.