Which structure prevents food from entering the windpipe?

The epiglottis is a flap-like structure located at the base of the tongue, which plays a critical role in the digestive and respiratory systems. Its primary function is to prevent food and liquids from entering the windpipe (trachea) during the act of swallowing. When you swallow, the epiglottis folds down over the opening of the larynx, effectively directing food and liquid into the esophagus rather than allowing it to enter the airway. This mechanism is essential for preventing choking and ensuring that the respiratory and digestive tracts function independently.

The other structures mentioned do not serve this specific protective function. The larynx is involved in voice production and also plays a role in protecting the trachea against food aspiration, but it does not actively close off the airway like the epiglottis does. The oropharynx is the part of the pharynx located behind the mouth, engaged in both respiration and digestion, but it does not prevent food from entering the windpipe. The trachea is the airway that carries air to the lungs, but it cannot prevent food from entering, as it does not have a mechanism to close off access during swallowing.