What is the epiglottis and what function?

Epiglottis

The epiglottis is a leaf-shaped flap of cartilage that helps to seal the trachea (and to prevent food from entering the windpipe) during the act of swallowing.

Function

During respiration (normal breathing) the epiglottis is erected, leaving the trachea open for the passage of air.

During swallowing, the epiglottis is folded down over the entrance of the trachea. Simultaneously the trachea is pulled upwards as the larynx is elevated. These actions prevent food or drink from entering the airway during swallowing.