The effectiveness of retia is primarily determined by how readily the heat, ions, or gases can be exchanged. For a given … See more

In birds with webbed feet, retia mirabilia in the legs and feet transfer heat from the outgoing (hot) blood in the arteries to the incoming (cold) blood in the veins. The effect of this biological heat exchanger is that the int… See more

Fish have evolved retia mirabilia multiple times to raise the temperature (endothermy) or the oxygen concentration of a body part above the ambient level.
In many fish, a rete mirabile helps fill the swim bladder… See more

In mammals, an elegant rete mirabile in the efferent arterioles of juxtamedullary glomeruli is important in maintaining the hypertonicity of the renal medulla. It is the hypertonicity of this zone, resorbing water osmotically from the renal c… See more

• Pampiniform plexus, a countercurrent heat-exchanging structure in the spermatic cord See more