Concurrent Exchange in Fish Gills: How Oxygen Transfer Works #2077672 (License: Personal Use)

The illustration depicts concurrent exchange in fish gills, where water and blood flow in the same direction, allowing continuous diffusion gradients for oxygen and carbon dioxide. Oxygen-rich water (100 → 50 units) transfers O₂ to deoxygenated blood (0 → 50 units), while CO₂ diffuses from blood to water. Though less efficient than countercurrent exchange, this mechanism still supports respiration in certain aquatic organisms.

Used in biology education and marine science resources to explain respiratory physiology in fish; matches user intent seeking visual clarification of gas exchange mechanisms in aquatic animals.