What structure prevents food from entering the trachea during swallowing?

The epiglottis is a crucial structure in the respiratory and digestive systems that plays a significant role in preventing food from entering the trachea during swallowing. It is a flap-like cartilage located at the base of the tongue, sitting above the larynx. During the swallowing process, the epiglottis folds down to cover the opening of the trachea, ensuring that the food bolus is directed into the esophagus instead. This mechanism is vital for protecting the airway from aspiration and ensuring that food and liquids go down the correct passage.

In contrast, the vocal cords are involved in phonation and help close the airway during activities such as coughing or during certain activities, but they do not prevent food from entering the trachea. The nasal septum is a structure that separates the nasal cavity and is not involved in swallowing; its function is related to airflow and nasal stability. The larynx, while it plays a part in protecting the airway during swallowing, does not actively close off the trachea like the epiglottis does. Therefore, the epiglottis is the structure specifically responsible for preventing food from entering the trachea during swallowing.