The upper respiratory tract refers to a set of anatomical structures that work together to carry air into the lungs. Together, the pharynx, larynx, nose, nasal cavity, and the mouth make up the upper respiratory tract, though these structures have have different functions. For example, the larynx or voice box controls speech and the pharynx or throat is used to carry food to the stomach. The upper respiratory tract is located just above the trachea. Anything beneath this area is considered the lower respiratory tract.
The nose is made up of external and internal portions, and the internal nasal cavity contains many structures. Nostrils are separated into two compartments, through which air is inhaled. Air is then taken through bony tubular openings referred to as the concha, which are considered facial bones. It then passes through internal nares, which contain capillaries, tiny hairs, and mucus. These tiny nasal hairs act as a filter and hold on to particles or bacteria that can cause illness or damage the delicate inner nasal passages.
The pharynx, or throat, is also part of the upper respiratory tract. After air passes through the internal nares, it enters the throat area. This nasal pharynx contains adenoids or tonsils that can be seen in the back of the throat. They can trap contaminants or bacteria that can also be harmful when ingested. The internal nares also contain eustachian tubes, which are used to stabilize air pressure within the ears.
The larynx is commonly referred to as voice box. It is used to produce sounds, as well as to block out any small particles of food that might otherwise enter the airway. Vocal cords, or folds, located within the larynx control the volume or pitch of the voice. They are located directly above the esophagus and trachea. This is where the lower and upper respiratory tract connect.
An upper respiratory tract infection is a common illnesses because it can develop in the nose, throat, or mouth area. These infections are considered colds, and they can produce varying symptoms, depending on where they develop. A sinus or nasal infection can produce a stuffy or drippy nose, while an infected larynx can cause changes in vocal sounds. An upper respiratory infection can be either viral or bacterial. There is no cure for a viral upper respiratory tract infection, but a bacterial infection can be treated with antibiotics.