The uvula is the dangling appendage visible at the back of the throat and the epiglottis is a cartilage flap within the throat. Situated behind the tongue and before the larynx, the usually upright epiglottis folds down to block the windpipe when a person swallows. This prevents swallowed items, such as food and drinks, from entering the lungs, directing them instead to the stomach.
The function of the uvula is more of a mystery. Some consider it obsolete, having evolved in the early forebears of humans, who would have leaned down to eat, as a way of guiding food and water down the throat.