Alveoli

Alveoli (singular alveolus) are tiny balloon-like sacs in the lungs. They are the site of oxygen and carbon dioxide exchange between the air and the blood. Through a process called diffusion, oxygen passes from the air in the alveoli into the red blood cells and carbon dioxide passes in the opposite direction. This exchange helps maintain a balance of oxygen and carbon dioxide levels in the body and is essential for respiration. Alveoli are also incredibly important for breathing and exchanging other hormones and gases such as nitric oxide. They are involved in a number of diseases such as emphysema and respiratory distress syndrome. Understanding how alveoli work is essential for research into treatments for such diseases.