Larynx structure and function respiratory system

  • Larynx structure, larynx, commonly called the voicebox, is located in the anterior throat and extends from the base of the tongue to the trachea. The larynx is a cartilaginous skeleton, some ligaments, and muscles that move and stabilize it and a mucous membrane. The laryngeal skeleton is nine cartilages: the thyroid cartilage, cricoid cartilage, epiglottis, arytenoid cartilages, corniculate cartilages, and cuneiform cartilages
Larynx

Sagittal section through the nasal cavity and pharynx.

Larynx Functions

  • It has three main functions: it (1) maintains an open airway, (2) protects the airway during swallowing, and (3) produces the voice. 
  • The larynx consists of nine cartilage structures: three singles and three paired. The cartilages are connected to one another by muscles and ligaments. The first single and largest cartilage is the thyroid cartilage, or Adam’s apple. The thyroid cartilage is attached superiorly to the hyoid bone. The second single and most inferior cartilage of the larynx is the cricoid cartilage, which forms the base of the larynx on which the other cartilages rest. The thyroid and cricoid cartilages maintain an open passageway for air movement.
Larynx

Anatomy of the Larynx. Image Source: openstax.org

  • The third single cartilage is the epiglottis. It differs from the other cartilages in that it consists of elastic cartilage rather than hyaline cartilage. Its inferior margin is attached to the thyroid cartilage anteriorly, and the superior part of the epiglottis projects superiorly as a free flap toward the tongue. The epiglottis protects the airway during swallowing. It prevents swallowed materials from entering the larynx by covering the glottis. As the larynx elevates during swallowing, the epiglottis tips posteriorly to cover the glottis. The three pairs of cartilages are on each side of the posterior part of the larynx.
  • The top cartilage is the cuneiform cartilage, the middle cartilage is the corniculate cartilage, and the bottom cartilage is the arytenoid cartilage. The arytenoid cartilages articulate with the cricoid cartilage inferiorly. The paired cartilages form an attachment site for the vocal folds. The larynx also houses the vocal cords. There are two sets of ligaments that extend from the posterior surface of the thyroid cartilage to the paired cartilages. The superior set of ligaments forms the vestibular folds, or false vocal cords, and the inferior set of ligaments composes the vocal folds, or true vocal cords.
  • When the vestibular folds come together, they prevent air from leaving the lungs, as when a person holds his or her breath. Along with the epiglottis, the vestibular folds also prevent food and liquids from entering from it. The vocal folds are the primary source of voice production. Air moving past the vocal folds causes them to vibrate, producing sound. Muscles control the length and tension of the vocal folds. The force of air moving past the vocal folds controls the loudness, and the tension of the vocal folds controls the pitch of the voice. An inflammation of the mucous epithelium of the vocal folds is called laryngitis. Swelling of the vocal folds during laryngitis inhibits voice production.

Further Readings