Air enters the respiratory system through the nose and mouth. The respiratory passage in the throat is called the pharynx and is made up of three parts. The epiglottis is a small flap of elastic cartilage that closes off the airway when food is swallowed. It controls the two passageways which lead to the lungs or stomach and prevents food from entering the lungs. The larynx is below the epiglottis and it is where your voice comes from.
The trachea (windpipe) is a large tube that runs down your throat below the pharynx. It branches into the two primary bronchi in the middle of the chest. Inside the lungs, the primary bronchi branch out into secondary bronchi. Around the lungs are twelve pairs of ribs which provide protection for the lungs and the heart.