The trachea branches into the two major bronchi: the right bronchus, which leads to the right lung, and the left bronchus, which enters the left lung. The trachea is another name for the windpipe and is a 4-inch conduit through which air travels on its way to the lungs.
Composed of cartilage, the trachea originates below the larynx and extends down behind the breast bone. Of the two bronchi, the right is shorter, wider and more vertical than its counterpart. It subdivides into three segments, while the left has only two. Like the trachea, the bronchi are made mostly of cartilage with a mucous membrane.