Where does the exchange of oxygen occur in the respiratory system?

The exchange of oxygen occurs in the alveoli, which are tiny air sacs located in the lungs. Each alveolus is surrounded by a network of capillaries, allowing for efficient gas exchange. When air is inhaled, it enters the alveoli where the oxygen from the air diffuses across the thin walls of the alveoli and into the bloodstream in the capillaries. This is essential for delivering oxygen to the body’s cells for cellular respiration and removing carbon dioxide from the blood.

The trachea serves as a passageway for air to travel to the lungs but does not facilitate gas exchange. The bronchi are the larger air passages that branch from the trachea into each lung and further divide into smaller bronchioles, also not directly involved in gas exchange. The pulmonary arteries carry deoxygenated blood from the heart to the lungs, but the actual exchange of gases occurs specifically at the alveolar level.