Human Respiratory System

Chapter Overview

Human Respiratory System provides an extensive analysis of external respiration, pulmonary gas exchange, and internal systemic gas delivery essential for cellular metabolism. The chapter begins by enumerating the physical properties required for efficient respiratory surfaces: large surface-area-to-volume ratio, thin moist barrier, high vascularity, and steep partial pressure diffusion gradients.

It traces the respiratory tract anatomy from the air-conditioning nasal cavity, pharynx, and cartilaginous larynx with vocal cords down into the lower respiratory tract-comprising the C-shaped cartilaginous trachea, primary bronchi, branching bronchioles, and terminal alveolar sacs wrapped in dense capillary networks. Students investigate ventilation mechanics, exploring thoracic volume changes produced by diaphragm contraction and external/internal intercostal muscle movements, along with negative intrapleural pressures that draw atmospheric air into the lungs.

The final modules evaluate blood gas transport biochemistry and respiratory pathology. It details oxygen transport via oxyhaemoglobin, sigmoid dissociation curves, and the Bohr effect, juxtaposed with the three modalities of carbon dioxide transport (dissolved plasma, carbamino compounds, and carbonic anhydrase-driven bicarbonate ions featuring the chloride shift). Finally, it compares haemoglobin with muscle myoglobin, and reviews etiology, symptoms, and prevention of upper and lower respiratory tract infections (sinusitis, otitis media, pneumonia, pulmonary tuberculosis) and chronic obstructive pulmonary diseases (chronic bronchitis and alveolar emphysema).