Upper Airway

The upper airway is the part of the respiratory tract located between the mouth and nasal cavity and the larynx. It is also commonly referred to as the pharynx. Its essential function is to filter, warm, and humidify the air that passes through the passages as a person breathes.

The primary structures of the upper airway are the nasal passages, the pharynx (throat), the larynx (voice box), and the trachea ( windpipe). The nostrils are the primary organs of smell and serve as the entryway to the upper airway, while the larynx, known as the voice box, generates sound.

Anatomy of the Upper Airway

The nasal cavity is divided into two sides, separated by a septum. Each nasal cavity features several conchae, thin bones projecting from the lateral walls, and two openings—the anterior nares, known as the nostrils. The nostrils contain cilia that filter the air entering the nasal cavity. Behind the nostrils is the vestibule, which is lined with hair and glands. The glands secrete mucus, which captures dust and other foreign particles in the air and trap them before they reach the lungs.

The pharynx, commonly referred to as the throat, is a cavity that extends from the nasal cavity to the larynx. It is separated into three parts: the nasopharynx, the oropharynx, and the laryngopharynx (also known as the hypopharynx). The nasopharynx is located behind the nose and serves as a passageway for air entering and leaving the nasal cavity.

The oropharynx is located between the soft palate and the epiglottis. It connects the oral cavity to the larynx and houses the palatoglossal and palatopharyngeal folds. The laryngopharynx is located in the deepest portion of the pharynx and serves as a passageway for air entering and leaving the larynx. It is also responsible for producing the characteristic sound of the human voice.

The larynx is a structure that contains the vocal cords and serves as a passageway for air entering and leaving the lungs. It is located between the pharynx and the trachea and is connected to the lungs by the trachea. At the base of the larynx is the epiglottis, a thin flap of cartilage that acts as a guard, preventing food and liquids from entering the trachea.

The trachea, also known as the windpipe, is a tube of cartilage and muscle that connects the larynx to the lungs. It extends from the larynx to the bronchi, which in turn, divide into two branches. These branches, known as the left and right main bronchi, connect the lungs to the trachea and provide the essential pathway for air to enter and leave the lungs.

Functions of the Upper Airway

The primary function of the upper airway is to filter, warm, and humidify the air that passes through the passages when a person breathes. The nose and the conchae contain specialized hair cells that trap foreign debris and allergens before they enter the lungs. The mucus produced by the glands of the vestibule captures additional particles that may have passed through the hair cells. All of these processes help to protect the lungs from damage.

The tone and volume of the voice are also produced in the upper airway. The larynx houses two vocal cords that vibrate as air passes through them, producing distinctive sounds. Depending on the speed and amount of air passing through the larynx, the sound produced will be higher or lower in pitch and volume.

Conclusion

The upper airway is an essential part of the respiratory system that serves to filter, warm, and humidify the air that a person breathes. Its primary structures are the nasal passages, the pharynx, the larynx, and the trachea. The primary functions of the upper airway are to protect the lungs from foreign matter and to produce the sound of the human voice.