Swallowing.
In the oral cavity, digestion begins when salivary amylase initiates the breakdown of carbohydrates.
The pharynx is a junction that opens to both the esophagus and the trachea (windpipe).
In the absence of food, the esophageal sphincter muscle is contracted and the epiglottis is up, allowing air to flow through the glottis and trachea to the lungs.