Vocal folds

The human larynx contains two pairs of folds made of elastic tissue covered by mucous membrane. One of them, the false vocal folds, narrows the glottis during swallowing, preventing pieces of food from getting into the trachea. Below them, there are are the true vocal folds, which, when appropriately adjusted, can be made to vibrate as air from the lungs passes out between them (see: phonation). The vibration produces voice, which is the essential component of voiced consonants as well as vowels. If the vocal folds are drawn apart, air flows between them causing no vibration, as in the production of voiceless consonants. The vocal folds are also called vocal cords.