The Nikon MicroscopyU confocal microscopy image gallery was created with a PCM-2000 confocal scanning system interfaced to a Nikon Eclipse E600 upright microscope. Images were recorded in successive z-axis serial sections with C-Imaging Systems software with excitation illumination provided by an argon-ion and/or a helium-neon laser.

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The term vocal cords can be somewhat misleading because these sound producing structures are not really chords but are folds of expandable tissue that extend across a hollow chamber known as the voice box. When engaged for speaking, the vocal folds can clock over 100 vibrations per second -- too fast for the unassisted eye to see. The voice box or larynx is located directly above the windpipe, which leads to the air passages of the lungs. When not used in speech, vocal cords remain open and lie close to the mucous membrane lining of the larynx. This provides flowing air with a direct and unobstructed pathway to the lungs and is vital for undisturbed breathing. Pitch is determined by frequency of the vibrations and higher-pitched sounds are typically produced by shorter and thinner folds that more often manifest in women and young children.

The surface layer of each vocal fold is loose enough to vibrate in a wave-like fashion over the underlying layers. Although the folds should open in a uniform and systematic manner, they do not completely open at once. Instead, the lower part first begins to open and the separation proceeds upward. This motion is often referred to as the mucosal wave. Importantly, vocal chords do not produce sound by vibrating like guitar strings. Instead, the repeated process of rapid openings and closings is produced by changes in air pressure. Just before speaking, muscles in the larynx bring the vocal folds together and allow air pressure from the respiratory tract to accumulate. Upon reaching a threshold point, a jet of air escapes between the folds causing them to vibrate, after which the folds collapse back together as air pressure proceeds to decrease.