(2) Oropharynx. The portion of the pharynx closely related to the digestive
system is the oropharynx. It is the portion of the pharynx below the soft palate and
above the upper edge of the epiglottis. (The epiglottis is the flap that prevents food from
entering the larynx (discussed below) during swallowing.)
(3) Laryngopharynx. That portion of the pharynx which is common to the
respiratory and digestive systems is the laryngopharynx. It is the portion of the pharynx
below the upper edge of the epiglottis. Thus, the digestive and respiratory systems lead
into it from above and lead off from it below.
The larynx, also called the Adam's apple or voice box, connects the pharynx with
the trachea. The larynx, located in the anterior neck region, has a box-like shape. See
figure 7-3 for an illustration. Since the voice box of the male becomes larger and
heavier during puberty, the voice deepens. The adult male's voice box tends to be
located lower in the neck; in the female, the larynx remains higher and smaller and the
voice is of a higher pitch.
a. Parts and Spaces. The larynx has a vestibule ("entrance hallway") which
can be covered over by the epiglottis. The glottis itself is the hole between the vocal
cords. Through the glottis, air passes from the vestibule into the main chamber of the
larynx (below the cords) and then into the trachea. The skeleton of the larynx is made
up of a series of cartilages.
b. Muscles. The larynx serves two functions and there are two sets of
muscles--one for each function.
(1) One set controls the size of the glottis. Thus, it regulates the volume of
air passing through the trachea.
(2) The other set controls the tension of the vocal cords. Thus, it produces
vibrations of selected frequencies (variations in pitch) of the moving air to be used in the
process of speaking.