THE LUNGS
The lungs are two cellular, sponge-like elastic organs, largely made up of little cavities of conical shape, which, in the regular alternations of two opposite respiratory movements of air, are at one time expanded, and then again compressed. The two lungs are not of equal size; the right lung is one-tenth larger in volume than the left.
THE TRACHEA, OR WINDPIPE,
Through which the air of the lungs enters and passes out, consists of from sixteen to twenty-six cartilaginous rings, posteriorly incomplete, lying horizontally one above the other.
These rings are connected by a membrane covering them externally and internally. As they enter the cavity of the chest, they divide into two branches, likewise composed of rings, one entering the right, the other the left lung. Before they join the lungs they divide again into several smaller branches, which again subdivide fork-like in the lungs, and terminate in numberless little grape-like clusters of hollow vesicles. The diameter of the trachea in adults is from one-half to three-fourths of an inch when at rest.
THE LARYNX
The larynx may be regarded as the funnel-shaped termination of the trachea. It enlarges upward and is composed of various cartilages more or less mobile, connected by ligaments and moved by muscles. The exterior of the larynx is formed by the
The cartilages in the interior are:
- The Arytenoid cartilages.
- Cartilages of Wrisberg.
- Cartilages of Santorini.
- Cuneiform cartilages.