Your lungs are a life-sustaining marvel, efficiently connecting the human body with the oxygen essential for functioning. Of all your internal organs, the lungs are the only ones to endure regular exposure to the outer environment, with healthy adults drawing in about 3,000 gallons of air daily, according to the U.S. Environmental Protection Agency. From this inhaled air, the lungs cull oxygen and deliver it to the bloodstream for distribution to the body’s organs and tissues. Gaseous waste in the form of carbon dioxide is collected from the tissues and exhaled. This respiratory process is a team effort between the varied structures of the lungs.

Anatomically Speaking

The lungs are located inside of your chest, one on each side. Each lung is divided into sections called lobes. Your right lung has three lobes, and the left has just two to allow room for the heart.

Air Travel

The respiratory system, of which the lungs form the foundation, is made up of an intricate network of tubes. When air enters the lungs by way of the mouth or nose, it is warmed in the throat before traveling down the windpipe, or trachea. At the bottom of the trachea, air is split between two passages -- the right and left main bronchus -- each of which leads into a lung.

Strictly Structures

The main bronchi enter the lungs and successively branch into thousands of smaller pathways called bronchioles. At the end of the bronchioles are air-filled structures called alveoli. The number of these spongy sacs is legion; you have about 300 million in each of your lungs, enough to cover an entire tennis court, says the American Thoracic Society. Inside the alveoli, an essential exchange of gas occurs as oxygen passes through their filmy walls into tiny blood vessels called capillaries. These minute structures transfer the oxygen to pulmonary veins, which then carry the oxygenated blood to the heart.

The Delicate Side

The structures of the lungs are efficient, but delicate; when exposed to irritants or infection, they reveal their vulnerability. Smoking, smog and exposure to mildew and allergens can inflame and constrict bronchial tubes. Pneumonia, influenza and cancer can disrupt the respiration process and progress to the point that longevity and quality of life are diminished. Your family physician or a pulmonary specialist can provide appropriate treatment and guidance to help keep your lung structures healthy and keep you breathing easy.