Metanephroi

Part of speech: noun

Definitions

1. A pair of elongated organs in the body of some vertebrates that are involved in filtration and excretion
2. Kidneys that develop from the embryonic mesoderm and function in the excretion of waste products in certain vertebrates
3. Organs found in the development of certain chordates that play a role in the regulation of water and electrolyte balance

Etymology: "Metanephroi" is the plural of "metanephros," the term for the permanent kidney that develops in the embryo after the earlier kidney forms have come and gone. The word is built from two Greek elements: "meta," meaning "after" or "behind," and "nephros," meaning "kidney." Put together, the name simply means "after the kidney," a label that describes its place in the sequence of development rather than its function. The "nephros" half is the same root that gives English "nephritis," an inflammation of the kidneys, and "nephrology," the study of kidney disease. Because the element was used across medicine, anatomists could assemble new terms from it as they described each stage of embryonic development. The plural form "metanephroi" follows the Greek pattern for nouns ending in "-os," which is why it looks different from the more familiar English plural.

Synonyms: kidneys