Gas exchange and transport
Gas transport depends on ventilation, diffusion, perfusion and hemoglobin binding. Oxygen and carbon dioxide follow partial-pressure gradients between alveoli, blood and tissues.
Open interactive lesson & self-check ↗Gas exchange and transport — learning map
Original conceptual SVG · scalableOriginal schematic relationship map for this topic; relationships are organized for study, not intended as an anatomical depiction or a diagnostic algorithm.
Alveolar diffusion
Oxygen diffuses toward pulmonary capillary blood; carbon dioxide diffuses into the alveolus. Barrier thickness and surface area influence transfer.
Oxygen carriage
Most arterial oxygen is bound to hemoglobin, with a small dissolved component; oxygen content depends on hemoglobin concentration and saturation.
Carbon dioxide carriage
Carbon dioxide travels dissolved, attached to proteins and mainly as bicarbonate after carbonic-anhydrase-mediated reactions in red cells.
V/Q matching
Ventilation–perfusion mismatch reduces the efficiency of oxygenation even if the lungs continue to receive air and blood.
Reference and next reading
Explore the original curriculum and publisher-hosted resources for full-depth reading; this note is an original schematic introduction, not an exhaustive chapter.