What is a flap tissue that closes the passage to trachea and lungs?

The flap of tissue that closes the passage to the trachea and lungs during swallowing is called the epiglottis. It is a thin, leaf-shaped piece of cartilage located at the base of the tongue and the top of the windpipe (trachea). When a person swallows, the epiglottis folds down over the opening of the trachea, preventing food or drink from entering the lungs. Once the swallow is complete, the epiglottis returns to its open position, allowing air to flow freely into and out of the lungs.