In the next three sections we’ll look at the parts of the head and neck that are involved in two vital functions: breathing, and eating and drinking. To get a preview of these major topics, we’ll look at a specimen that’s been divided in the mid-line.
The passage for air, and the passage for food and liquid, begin separately at the nose and the mouth. Air passes backward through the nasal cavity, and the nasopharynx. Food and liquid pass backward through the oral cavity. The two passages unite here.
Air, food and liquid all pass through this common passage, the oropharynx. The two passages separate again here, in the hypopharynx. Food and liquid pass backward into the esophagus on their way to the stomach. Air passes forward through the larynx and into the trachea, on its way to the lungs.
So the lines of travel for air, and for food and liquid, cross over in the oropharynx. It’s important that air on the one hand, and food and liquid on the other hand, don’t pass upward or downward into the wrong passage.
To take care of this, there are important mobile structures above and below the oropharynx that act as separators. These are the soft palate above, and the epiglottis, and vocal cords below.
As we’ll see in later sections of this tape, the structures that form the passages for air, and for food and liquid, are also involved in a further important function: the production of voice sounds.