The larynx commonly called the voice box. IT is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration.
It changes pitch and volume. The larynx houses the vocal folds (vocal cords), which are essential for phonation& sound. The vocal folds are situated just below where the tract of the pharynx into the trachea and the esophagus.
Structure:-
(1)Cartilages:-Posterior view of the larynx is cartilages (left) and intrinsic muscles (right)
There are nine cartilages, three unpaired and three paired, that support the mammalian larynx and form its skeleton.
Unpaired cartilages:
• Thyroid cartilage: This forms the Adam’s apple. It is usually larger in males than in females. The thyrohyoid membrane is a ligament associated with the thyroid cartilage that connects the thyroid cartilage with the hyoid bone.
• Cricoids cartilage: A ring of hyaline cartilage that forms the inferior wall of the larynx. It is attached to the top of trachea.
• Epiglottis: A large, spoon-shaped piece of elastic cartilage. During swallowing, the pharynx and larynx rise. Elevation of the pharynx widens it to receive food and drink; elevation of the larynx causes the epiglottis to move down and form a lid over the glottis, closing it off.
Paired cartilages:
• Arytenoid cartilages: Of the paired cartilages, the arytenoid cartilages are the most important because they influence the position and tension of the vocal folds. These are triangular pieces .
• Corniculate cartilages: Horn-shaped pieces of elastic cartilage located at the apex of each arytenoid cartilage.
• Cuneiform cartilages: Club-shaped pieces of elastic cartilage located anterior to the corniculate cartilages.
Muscles:-The muscles of the larynx are divided into intrinsic and extrinsic muscles.
The intrinsic muscles are divided into respiratory and the muscles (the muscles of phonation). The respiratory muscles move the vocal cords apart and serve breathing. The phonatory muscles move the vocal cords together and serve the production of voice.
The extrinsic, passing between the larynx and parts around; and intrinsic, confined entirely. The main respiratory muscles are the posterior cricoarytenoid muscles. The muscles are divided into adductors .
