Final answer:
The epiglottis is a flexible structure that covers the glottis to prevent food and drink from entering the larynx during swallowing.
Step-by-step explanation:
The spoon or leaf-shaped structure of the larynx that folds over during swallowing to prevent food and drink from entering the larynx is the epiglottis. This very flexible piece of elastic cartilage is attached to the thyroid cartilage and swings into a 'closed' position to cover the glottis (the opening of the larynx).
The epiglottis acts as a protective mechanism, blocking access to the trachea and bronchi to prevent aspiration of food into the respiratory tract. When swallowing, the laryngeal muscles constrict, and the pharynx and larynx lift upward while the upper esophageal sphincter relaxes, allowing food to enter the esophagus.
The closure of the epiglottis, combined with the rising of the soft palate and uvula, which close off the nasopharynx, ensures that swallowed material bypasses the airways and enters the digestive tract safely.