The human lungs are amazing feats of nature. They pump vital oxygen through airways and into the bloodstream every second of every day. Without this ability, humans could not survive on Earth.

This book explains the science behind the amazing human respiratory system. It also sheds light on how easily a healthy respiratory system can be damaged, whether by a viral or bacterial infection or through detrimental habits such as smoking. But there are many treatments to keep the airways free and clear, and this book also describes the many different approaches doctors can take to save patients’ lives and lungs.

The anatomy of the human respiratory system starts at the place where air fi rst enters the body—the nose. This structure provides humans with the sense of smell while also fi ltering, warming, and moistening inhaled air.

Air that passes through the nose travels to the pharynx, or throat, the cone-shaped passageway leading from the mouth and nose to the larynx, or voice box. The larynx
is a hollow tube connected to the top of the windpipe, and this air canal to the lungs not only enables humans to speak but also keeps food out of the lower respiratory tract.

After passing through the larynx, air travels through the trachea, also known as the windpipe. Here, the air is cleansed and moistened before entering the lungs. The clean air then travels into the deep tissues of the lungs, eventually reaching the region where gas is exchanged, the centre of the respiratory system.