The lungs are two spongy, cone-shaped organs in the chest that are responsible for breathing. They are part of the respiratory system and play a crucial role in delivering oxygen to the body and removing carbon dioxide. The lungs contain millions of small air sacs called alveoli, which are surrounded by tiny blood vessels called capillaries. When air is inhaled, it travels through the airways and reaches the alveoli, where oxygen is exchanged for carbon dioxide. The lungs are protected by the rib cage and are lined with a thin membrane called the pleura.