The respiratory tract divides into a conducting portion and a respiratory portion; the conducting portion—comprising the nasal cavity, nasopharynx, larynx, trachea, bronchi, and bronchioles—functions to warm, moisten, and clean inhaled air before it reaches the gas-exchange regions of the lung. Key structures include the epiglottis, an elastic cartilage flap lined by stratified squamous epithelium that closes over the laryngeal airway during swallowing to direct food into the esophagus rather than the airway, and the trachea, supported by cartilage rings and lined by respiratory epithelium. This is a topic within respiratory histology/anatomy, establishing the structural-functional organization of the upper and conducting airways as a foundation for understanding lower respiratory (gas-exchange) histology.
The respiratory tract divides into a conducting portion and a respiratory portion; the conducting portion—comprising the nasal cavity, nasopharynx, larynx, trachea, bronchi, and bronchioles—functions…