Upper Portion of the Respiratory Tract ‒ Section

Both respiratory rate and depth are regulated by the brain’s respiratory centers, which respond to factors like chemical and pH changes in the blood. These changes are detected by central chemoreceptors in the brain and peripheral chemoreceptors located in the aortic arch and carotid arteries. The floor of the nasal cavity is formed by the palate. In the anterior region, the hard palate is composed of bone, while the posterior soft palate consists of muscle tissue. Several bones that form the walls of the nasal cavity contain air-filled spaces called the paranasal sinuses, which help to warm and humidify incoming air. Each paranasal sinus is named for the bone it is associated with: frontal sinus, maxillary sinus, sphenoidal sinus and ethmoidal sinus. The sinuses produce mucus and lighten the weight of the skull. The uvula is a small, teardrop-shaped structure located at the apex of the soft palate. During swallowing, the uvula and soft palate swing upward to close off the nasopharynx, preventing food or liquid from entering the nasal cavity. Deeper in the nasal cavity is the olfactory epithelium, which detects odors. The nasopharynx, flanked by the nasal cavity’s conchae, serves solely as an airway and houses the pharyngeal tonsils at its upper end. *LICENSES AND ATTRIBUTIONS CC licensed content, Shared previously, The Process of Breathing, Authored by: OpenStax College. License: CC BY: Attribution. License Terms: Download for free at http://cnx.org/contents/AQNhNZty@1.1:u67b9E14@6/The-Process-of-Breathing* ## Keywords section of the upper airways, nose, nasal cavity pharynx nasopharynx