Explain in detail how air enters & leaves the lungs

The lung is a branching system of tubes and air sacs. Air enters the nose and mouth and is directed in the throat to the trachea which carries the air in the chest. The trachea splits into two major bronchi, one for each lung. The bronchi branch into smaller and smaller tubes that end ending in air sacks (alveoli) where the gas exchanges occur. Adult lungs contain about 600 million alveoli, air-filled sacs that are surrounded by capillaries. Oxygen in the inhaled air enters the capillaries in alveoli and attaches to hemoglobin molecules. At the same time, carbon dioxide leaves the capillaries and enters the alveoli. The carbon dioxide leaves the lungs when you exhale.