mucosal lining of larynx 00-13-49

mucosal lining of larynx 00-13-49 - Home Vocal Topics Why...

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The Larynx: Structure and Function (Page 3 of 3) Mucosal Lining of the Larynx The vocal apparatus consists of two pairs of mucosal folds : the vestibular folds (‘false vocal cords’) and the true vocal folds. The vestibular folds are located above both sides of the glottis (the hole and the ligament itself). They are covered by respiratory epithelium, and do not contain muscle. They are created by the mucosa passing over the vestibular ligament . They vibrate somewhat during phonation and especially during vibrato singing. Although they do play a role in resonance, these false folds, unlike the true vocal folds, are not actually responsible for sound production. The false vocal folds also work with the epiglottis to create a seal so that nothing goes down the trachea (windpipe) during swallowing. Vocal fold ’ is the current term for ‘vocal cord’. (Most teachers and singers use these two terms interchangeably.) The change in terminology came about as the anatomy of the larynx, including the structure and function of the folds, came to be better understood by the scientific world. The folds are not a band of string suspended in the air that vibrates when it is plucked or struck, as the word ‘cord’ suggests. Instead, they are part of a muscle on the side of the larynx that is covered with special tissues that can vibrate at a high speed. (Only its outer covering actually vibrates.) A vocal fold resembles a lip of tissue much more than a cord, and the term ‘fold’ is, therefore, more accurate and preferable. The true vocal folds are a pair of pliable shelves of tissue that stretch horizontally across the top of the larynx. They may also be described as twin infoldings covered on the surface by laryngeal mucous membrane (made up of elastic and fatty tissue, or stratified squamous epithelium), which is supported deeper down underneath by the innermost fibres of the thyroarytenoid muscle . They are flat, triangular bands, and are pearly white in colour. Unlike the false vocal folds, the true vocal folds do contain skeletal muscle. In most males, the vocal folds are longer and thicker and have more mass, producing a deeper pitch. The folds are attached at the back to the vocal process of the arytenoid cartilages and to the thyroid cartilage at the front. They are enclosed within the thyroid cartilage, which is the hard structure that forms the mass in the neck known as the Adam’s apple. Their outer edges are attached to muscle in the larynx and do not move or vibrate, while their inner edges, or margins, are free to vibrate. Most of the muscles that act to abduct (open) or adduct (close) the vocal folds attach to the muscular process of the arytenoid cartilages. There is only one muscle that has an abductor action on the vocal folds - the posterior cricoarytenoid muscle - although there are several that act to adduct the folds. Abduction of the vocal folds may be accomplished either by externally rotating the arytenoid cartilages on a pivot located at
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This note was uploaded on 11/13/2010 for the course CODS 361 taught by Professor Gel during the Spring '10 term at WPUNJ.

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mucosal lining of larynx 00-13-49 - Home Vocal Topics Why...

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