The part of the respiratory system responsible for gas exchange is the alveoli. These tiny, balloon-like structures are located at the end of bronchioles in the lungs. Alveoli provide a vast surface area for the exchange of oxygen and carbon dioxide between the air and the bloodstream. Oxygen diffuses from the air in the alveoli into the surrounding capillaries, while carbon dioxide moves from the blood into the alveoli to be exhaled. This efficient gas exchange is crucial for cellular respiration and maintaining the body’s oxygen levels.