Fig. 20.1. Embryology of nephrons.

Fig. 20.2. Vertebrate nephrons

Fig. 20.3. Comparative anatomy of nephrons and their blood supply.

Fig. 20.4

Fig. 20.5. Evolution of kidneys and ducts.

Fig. 20.6. Stages in the development of an amniote kidney.

Fig. 20.7. The ureteric bud induces metanephros to form.

Fig. 20.8. Cloacal regions.

Fig. 20.9. Three most common types of nitrogenous waste.

Large renal corpuscle means more water in raw filtrate Thick intermediate segments mean many cilia to drive filtrate through tubule, which means less water will be reabsorbed One extreme: marine teleosts and mammals - concentrated urine Other extreme: freshwater teleosts and sharks - copius dilute urine Fig. 20.10. Nephron structure in representative craniates.

Red - water or ions into body Green - urine or ions out of body Fig. 20.11. Osmoregulation by “fishes.”

Fig. 20.12. Osmoregulation by tetrapods.

Fig. 20.13

Fig. 20.14

Fig. 20.15