Fig. 84. The air passages of the head and throat.
Pharynx, larynx, and trachea
There is only one tube leading from the back of the nasal passage to the lungs. Different parts of this tube are given different names. The pharynx is that part that extends from the back of the nose to the vocal chords. The larynx is the part of the throat where the vocal chords are located. We sometimes call it the "Adam's apple." It is very prominent in some men, but seldom noticeable in women. The trachea is the part of the tube leading down from the larynx. At the lower end of the trachea the tube divides into two parts that we call the bronchi, one leading to each lung.
The bronchi
The bronchi carry the air from the trachea to the lungs. They divide again and again until they become so small that there is a branch for each little air cell in the lungs.
Fig. 85. The lungs.
The lungs
The lungs are the most important part of the respiratory system. They are made up of lobes. There are two lobes in the left lung and three in the right. Each lobe is divided into lobules, which means small lobes. Each lobule is divided into air spaces. In these air spaces, or cells, the work of the lungs is performed.