Keuhkorakkula

Keuhkorakkula, also known as an alveolus, is a microscopic air sac in the lungs of mammals. These tiny structures are the primary sites of gas exchange, where oxygen from inhaled air diffuses into the bloodstream and carbon dioxide from the blood diffuses into the air to be exhaled. Each lung contains millions of these thin-walled sacs, which collectively provide an enormous surface area for efficient respiration. The walls of the keuhkorakkula are incredibly thin, typically only one cell thick, and are covered in a dense network of capillaries. This close proximity between air and blood facilitates the rapid transfer of gases. The inner surface of the keuhkorakkula is also lined with a thin layer of fluid containing surfactant, a substance that reduces surface tension and prevents the sacs from collapsing during exhalation. The collective function of these numerous keuhkorakkulat is essential for maintaining oxygen levels in the body and removing waste carbon dioxide.