1 - Introduction: Embryonic Kidneys and Other Nephrogenic Models

Abstract

This chapter provides an overview of the kidney and discusses the development and function of the embryonic kidneys—the pro- and meso-nephroi—in detail. The embryonic kidney of amphibians and fish is known as the “pronephros,” “head kidney,” or “vorniere,” while their adult kidney is known as a “mesonephros,” “Wolffian body,” or “urniere.” In some instances, permanent mesonephroi of fish and frog are referred to as “opisthonephroi,” a term used to distinguish them from the transient mesonephroi of amniotes. Upon development of the adult kidney, the embryonic kidney either degenerates or becomes a part of the male reproductive system. Mesonephric kidneys are more complex in organization and consist of a linear sequence of nephrons linked to the nephric duct. Mesonephric nephrons contain internal glomeruli and in some instances, particularly in anterior mesonephric tubules, also link to the coelom via ciliated tubules called “peritoneal funnels.” In animals in which the mesonephros is the terminal kidney such as amphibians and fish, the final organ is very complex containing a large number of nephrons, most of which have an internal glomerulus. This chapter provides a useful resource to explore many advantages of the simple kidneys as model organogenesis systems.