In Depth: Lung The cone-shaped lungs are sponge-like organs that fill the chest cavity and make up most of the lower respiratory tract. Their most important job is providing oxygen to capillaries so they can oxygenate blood. Each lung is divided into lobes. The right lung has three, but the left lung has only two to accommodate the heart. Together, the lungs’ tissue surface is almost 40 times greater than the body’s outer surface, making the lungs (together) one of the largest organs in the body. Each lung houses a bronchial tree, which gets its name from the intricate network of air passages that supply the lungs with air. The air-filled sacs in the lungs called alveoli resemble grape clusters. White blood cells known as macrophages, located inside each alveolus, ingest and destroy airborne irritants that enter the lungs. After you exhale, the lungs stay partly inflated because of a fluid called surfactant that is produced by special cells and secreted within the alveoli. Surfactant contains fatty proteins and helps to prevent lung infections.
Posted on: Fri, 16 Aug 2013 22:22:13 +0000
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