The epiglottis is a flap of tissue in your throat that helps you swallow. It covers the windpipe when you eat or drink, to prevent food or liquid from entering your lungs. Full definition
You see, we have a valve - medically known as epiglottis - that prevents you from actually vomiting what you just ate. (momwoot.com)
During obligate nose breathing the newborn's epiglottis elevates and forms an interlock with the soft palate, allowing the newborn to breathe and swallow at the same time. (brianpalmerdds.com)
An underdeveloped epiglottis is mainly the reason why babies spit - up. (momwoot.com)