pronephrons

Noun

pronephron (plural pronephrons)

1. The first part of the urogenital system to be differentiated in a vertebrate embryo, which functions as a simple excretory organ in simpler forms, serves as a provisional kidney in some fish and amphibians, and only appears as a temporary embryonic structure in reptiles, birds, and mammals.
   • In addition, while in the pronephron only vacuolization was noted, the structure of the liver had an atypical appearance and there was a considerable number of erythrocytes scattered among the hepatic chords which themselves were noticeably altered.1975, Acta Embryologiae Experimentalis, page 110

   Synonyms:

   pronephros