Applied anatomy and physiology of the respiratory tract

Nasal Cavity

Part of the upper respiratory tract that warms, filters, and humidifies air

Pharynx

Passageway from posterior nares to esophagus and larynx

Larynx

Contains vocal cords and epiglottis to protect airway during swallowing

Trachea

Tube-like structure from larynx to bronchial tree, with c-shaped rings

Carina

Point of tracheal bifurcation into bronchi

Lung Segments

Divided into lobes with bronchial tubes connecting segments

Bronchioles

Small airways branching from bronchi, 1-2 mm in diameter

Cilia

Hair-like structures on cells that move debris towards pharynx

Mucous

Gel/sol layers in airway mucosa aiding in debris removal

Muco-ciliary Escalator

System of cilia and mucus moving debris towards pharynx

Conducting Zone

Pathway for gas flow to respiratory zone, includes trachea and bronchioles

Respiratory Zone

Site of gas exchange, includes alveoli and bronchial tubes

Alveolus

Air sacs where gas exchange occurs, containing different types of alveolar cells

Type I Alveolar Cell

Forms alveolar walls and facilitates gas exchange

Type II Alveolar Cell

Produces surfactant to prevent alveolar collapse

Type III Alveolar Cell

Alveolar macrophage that phagocytizes debris

Alveolar-Capillary Membrane

Site of gas exchange between alveoli and capillaries

Capillaries

Surround alveoli for gas exchange, allowing oxygen and carbon dioxide diffusion