Final answer:
The flap of cartilage referred to in the question is the epiglottis, which is essential for protecting the airway during swallowing by covering the windpipe.
Step-by-step explanation:
The flap of cartilage that comes from the Greek for "above" and "tongue" is the epiglottis. The epiglottis is a leaf-shaped piece of elastic cartilage that plays a critical role in the human respiratory and digestive systems by sealing off the windpipe during swallowing, preventing food and beverages from entering the lungs.
Attached to the thyroid cartilage, the epiglottis rests on the glottis when in the closed position. During swallowing, the pharynx and larynx lift upward, expanding the pharynx and allowing the epiglottis to swing downward.
This anatomical behavior effectively closes the opening to the trachea, enabling a safe passage for food to enter the esophagus without compromising the airway.