Pathophysiology
Clinical meaning
The respiratory system is responsible for gas exchange, the continuous process of delivering oxygen from the atmosphere to the blood and removing carbon dioxide from the blood to the atmosphere. Understanding respiratory anatomy, physiology, and pathophysiology at the cellular level is essential for practical nursing practice because respiratory assessment findings directly reflect underlying cellular processes, and nursing interventions are designed to optimize cellular oxygenation. Anatomy of the Respiratory System: The respiratory system is divided into the upper and lower respiratory tracts. The upper respiratory tract includes the nose, pharynx (nasopharynx, oropharynx, laryngopharynx), and larynx. These structures warm, humidify, and filter inspired air. The nasal cavity contains turbinates (conchae), shelf-like structures covered with highly vascular mucous membrane that increase the surface area for warming and humidifying air. The mucous membrane contains goblet cells that secrete mucus, trapping particles larger than 10 micrometers in diameter. The nasopharynx contains adenoid tissue (pharyngeal tonsils) that provides immune surveillance. The larynx contains the vocal cords and the epiglottis, a cartilaginous flap that closes over the laryngeal inlet during swallowing to prevent aspiration. The lower respiratory...