What is the flap in your esophagus called?

The name of the structure at the top of the esophagus is the "epiglottis". This structure is very important in protecting the vocal cords, trachea, and the lungs. It does this by covering the opening to the vocal cords and making an airtight seal. It also holds air in our lungs so we can form a cough, and produce extra pressure in our lungs, called "peep" (positive end expiratory pressure). So, it is actually a very important organ.