Data

Copy and paste the text below. It is read-only. Select All

Sphincter A ringlike muscle which closes an orifice or passage Aryepiglottic Sphincter • Muscle fibers embedded in aryepiglottic fold surrounding pear shaped opening (aditus) into laryngeal cavity. • First line of defense against foreign objects. • Closes during swallowing and vomiting--preventing entry of food, liquid or vomitus into respiratory tract. • Opening is called upper sphincter of larynx. Upper Ventricular Sphincter • Lies between laryngeal vestibule and ventricle. • During normal phonation, ventricular folds remain in quiet, open position. • When the ventricular muscles contract, they meet at midline, sealing or closing the sphincter. • True vocal folds will always adduct first, however. • Increases subglottic pressure by adding another "door" to keep air in lungs and foreign objects out. Middle True Vocal Fold Sphincter • Third door of closure. • Not effective in preventing outflow of air during effort closure. • Third line of defense in keeping foreign objects our of lungs. • May close independently of other two sphincters. • All three sphincters close during swallowing. • Opens and closes rapidly as we are phonating lower