Cue Column | Note-Taking Area
What does the nasal cavity do? | Warms incoming air to body temperature, moistens it, and filters particles via mucus and cilia. The mucociliary lining is the first line of defense.
What is the pharynx? | A common passageway for both the respiratory and digestive systems (food and air share this space). Leads to larynx (air) and oesophagus (food).
What is the larynx? | The voice box — contains the vocal cords responsible for sound production. Guards the lower airway; closes during swallowing to prevent aspiration.
What is unique about the trachea? | Reinforced by C-shaped hyaline cartilaginous rings. The open side of each C faces posteriorly (toward oesophagus) to allow oesophageal expansion during swallowing. The rings prevent collapse.
Primary vs secondary bronchi? | Right primary bronchus is shorter, wider, and more vertical than the left → inhaled foreign objects more likely to lodge in the right bronchus.
What are bronchioles? | Smallest airways without cartilage. The terminal bronchioles are the end of the conducting zone; respiratory bronchioles begin the respiratory zone where gas exchange starts.
What are the alveoli? | Approximately 700 million tiny air sacs providing ~70 surface area. Terminal units where gas exchange occurs. Lined by Type I cells (thin, gas exchange) and Type II cells (produce surfactant, prevent collapse).
What is the pleura? | Double-layered membrane (visceral and parietal). Intrapleural space contains fluid that lubricates lung movements. Slightly negative intrapleural pressure keeps lungs inflated.
Summary
The respiratory tract is divided into the conducting zone (no gas exchange: nares to terminal bronchioles) and the respiratory zone (gas exchange: respiratory bronchioles to alveoli). Each segment has structural adaptations — cartilaginous rings in trachea, cilia in bronchi, and enormous surface area in alveoli.