A small structure with a big job

Our voice begins in the larynx, or voice box, where two small bands of tissue called the vocal folds stretch across the airway. When we speak, air from the lungs passes between them and causes their surfaces to vibrate, producing sound. Those vibrations can occur 2 hundreds of times every second. To withstand that repeated motion, vocal folds need an unusual combination of properties. They must be strong enough to tolerate constant mechanical stress, yet soft and flexible enough to vibrate smoothly. Their layered structure makes this possible. The outer surface is covered by a thin layer of cells called the epithelium, which forms a protective barrier. Beneath it lies soft connective tissue that allows the surface to move in a wave-like motion during speech. Deeper layers provide strength and elasticity, while muscle controls the position, shape, and tension of the vocal folds. Together, these layers turn airflow from the lungs into the sound we recognize as voice. This sophisticated structure also creates a challenge when the tissue is injured. A vocal fold cannot simply close a wound. It must rebuild itself while preserving the delicate physical properties required for vibration.

Dr. Cai's fellowship is under the supervision of Dr. Susan Thibeault and Dr. Vlasta Lungova at UW-Madison's Department of Otolaryngology-Head and Neck Surgery, School of Medicine and Public Health.