Role in Respiration
Unlike the trachea and bronchi, the upper airway is a collapsible, compliant tube. As such, it has to be able to withstand suction pressures generated by the rhythmic contraction of the diaphragm that sucks air into the lungs. This is accomplished by the rhythmic contraction of upper airway muscles, such as the genioglossus (tongue) and the hyoid muscles. In addition to rhythmic innervation from the respiratory center in the medulla oblongata, the motoneurons controlling the muscles also receive tonic innervation that sets a baseline level of stiffness and size.
Read more about this topic: Upper Respiratory Tract
Famous quotes containing the word role:
“Whatever we’re doing, whoever we are, it isn’t enough. . . . Little wonder we have trouble finding role models to guide us through these shoals. No one less than God Herself could be all the things we’d like to be to all the people we’d like to feel approval from.”
—Melinda M. Marshall (20th century)