The organ responsible for breathing in the human body is the lungs. These vital organs play a crucial role in the respiratory system by facilitating the exchange of oxygen and carbon dioxide. When we inhale, the diaphragm and intercostal muscles expand the chest cavity, drawing air into the lungs. Oxygen from the inhaled air diffuses into the bloodstream, where it is transported to cells throughout the body. Simultaneously, carbon dioxide, a waste product of metabolism, moves from the blood into the lungs to be exhaled. The lungs' structure, including alveoli, maximizes this gas exchange process.