Final answer:
The epiglottis prevents the aspiration of food and liquids by folding over the glottis to cover the trachea during swallowing, while the cough reflex expels any mistakenly swallowed material.
Step-by-step explanation:
The epiglottis plays a crucial role in preventing the aspiration of foods and liquids during the act of swallowing. As one begins to swallow, a series of reflexive actions occur: the soft palate and uvula rise to close off the nasopharynx, the larynx moves upward, and the epiglottis, which is a piece of flexible cartilage attached to the thyroid cartilage, folds downward to cover the glottis (the opening to the larynx). This action effectively blocks the trachea, directing the swallowed material into the esophagus. If food accidentally enters the trachea, it triggers a cough reflex to expel the material, thus protecting the lower respiratory tract from foreign substances.
Sometimes referred to as deglutition apnea, breathing temporarily stops during swallowing to ensure that the swallowing mechanism can occur without interference from the respiratory process. The coordination of these actions ensures that the airway is protected and that swallowing is a safe process.