Figure 1-5. The nose.
b. Pharynx. The pharynx (FAIR-inks) is the common posterior space for the
respiratory and digestive systems. It is about 13 cm or 5 inches long and is shaped a
little like a funnel. It starts at the internal nares and extends partway down the neck.
The wall of the pharynx is made up of skeletal muscles and lined with a mucous
(1) Function. The pharynx has two functions: it serves as a passageway
for air and food, and it provides a resonating chamber (amplifying sounds) for speech
(2) Divisions. The pharynx can be divided into three parts: the
nasopharynx, the oropharynx, and the laryngopharynx.
(a) Nasopharynx. The part of the pharynx specifically related to the
respiratory system is the nasopharynx. It is located above the soft palate. The two
posterior openings (nares or nostrils) of the nasal chambers lead into the single space
of the nasopharynx. The auditory tubes (also called the eustachian tubes) open into the
nasopharynx. The auditory tubes connect the nasopharynx with the middle ears to
equalize the pressure between the outside and inside of the eardrum. The pharyngeal
tonsils (adenoids) are located in the upper posterior wall of the nasopharynx. The soft
palate, floor of the nasopharynx, is a trapdoor which closes off the upper respiratory
passageways during swallowing.
(b) Oropharynx. This is the part of the pharynx which is closely related
to the digestive system. It is located below the soft palate and above the upper edge of
the epiglottis. (The epiglottis is the flap that prevents food from entering the larynx