Structure & Function of the Lungs

Updated April 17, 2017

Adults average 15 to 20 breaths per minute, which comes out to over 20,000 breaths per day. The lungs are an essential component of that process and work in conjunction with the nose, throat and windpipe to bring fresh oxygen into the body, thereby supplying all the cells with life-sustaining energy.


The right lung is separated into three lobes (sections), and the left lung is separated into two, as the right lung is the slightly larger of the two. Lung USA describes each lobe as a "balloon filled with spongelike tissue." Air moves in and out of the lobes through a branch of the bronchial tubes. Each lobe is surrounded by the pleura, a membrane that is folded onto itself, which separates the lungs from the wall of the chest.

Bronchus System

After air is breathed in, it moves down into the trachea which eventually splits into the right and left bronchus, large pathways that carry the air into the lungs. The bronchus then divides into bronchioles, which are found in the lungs as well. At the end of the brochioles are alveoli, small air sacs surrounded by connective tissues that hold blood vessels.

Pleural Cavity and Diaphragm

As aforementioned, the pleura separates the lungs from the chest. The space in between is known as the pleural cavity, an area with a small amount of fluid. If large amounts of fluid, blood or air enter that cavity, the lungs collapse. The diaphragm is located directly underneath, and it divides the chest cavity from the abdomen. When you breathe in, the diaphragm flattens out in order for the lungs to expand.

Gas Exchange

When oxygen reaches the lungs, it passes into the bloodstream which carries it to every last cell in the body. At the cells, the oxygen is exchanged for carbon dioxide, a waste gas. The bloodstream then carries the carbon dioxide back into the lung, at which point it is exhaled and the substance leaves the body. Gas exchange sustains human life because the entire body needs oxygen.

Abnormal Functioning

If the process of gas exchange is not working correctly, you will display symptoms such as chronic cough or chest pain, shortness of breath, chronic mucus production, wheezing or coughing up of blood. Since fresh and clean oxygen and the elimination of carbon dioxide is so vital to your well-being, you should consult a health professional immediately if any of the above signs occur.

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About the Author

Jen Marx holds a Master of Arts in English and American literature. She is a consultant at a university writing center and has numerous print and online publications, including "Community College Campus News." Marx specializes in topics ranging from wedding planning to history to the environment.