The Human Respiratory System - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 30

Fig. 2.10 Larynx opening at the glottis, showing the vocal and vestibular folds that separate the
region into sub-cavities

bends down and meets the corniculate cartilages to close off the pathway to the
trachea.

• The cuneiform cartilages —small elongated rod-like elastic cartilages located at

the apex of each arytenoid cartilage, and at the base of the epiglottis above and
anterior to the corniculate cartilage.

The airway cavity of the larynx extends from a triangular shaped inlet at the epiglot-
tis to a circular outlet inferior to the cricoid cartilage where it is continuous with
the lumen of the trachea. Two pairs of mucous membrane foldings stretch inward
and horizontally across the larynx. The upper pair of folds are the vestibular folds
( ventricular or false folds ) which only play a minimal role in phonation but protect
the more delicate folds below. The lower pair of folds are the true vocal folds, which
form a slit-like opening called the glottis. This is the narrowest part of the larynx. The
vestibular and vocal folds divide the larynx into (1) the vestibule (upper chamber),
located above the vestibular folds; (2) the ventricle, the small middle chamber located
between the vestibular and vocal folds; and (3) the infraglottic cavity, which extends
from the vocal folds to the lower border of the cricoid cartilage (Fig. 2.10 ). The vocal
cords, are flat triangular bands and white in colour because of their their lack of blood
supply (avascular) nature. They are attached posteriorly to the arytenoid cartilages,
and anteriorly to the thyroid cartilage. The interior surface of the superior portion
of the larynx is made up of stratified squamous epithelium which is an area that is
subject to food contact. Below the vocal folds the epithelium is pseudo stratified cil-
iated columnar. Here mucociliary action directs mucous movement upward towards
the pharynx, so that the mucous is continually being moved away from the lungs.

2.4.2 Physiology of the Larynx

The ciliated mucous lining of the larynx further contributes towards the respiratory
system's ability to remove foreign particles and to warm and humidify the inhaled air