Pronephros
Mesonephros
Metanephros
Pronephros is the first of the three developmental kidney structures in vertebrates. It forms during the early embryonic stage but is non-functional and eventually degenerates.
Mesonephros is the second developmental kidney structure, which forms during the intermediate stage of embryonic development. It functions as the primary excretory organ in fish and amphibians. In mammals, the mesonephros only functions temporarily during embryonic development before being replaced by the third kidney structure.
Metanephros is the final and most developed kidney structure in vertebrates. It forms during the later stages of embryonic development and becomes the functional kidney in adults. The metanephros is responsible for filtering blood and producing urine, playing a vital role in maintaining homeostasis in the body.