]> pronephros Once the more complex mesonephros forms the pronephros undergoes apoptosis in amphibians. In fishes the nephron degenerates but the organ remains and becomes a component of the immune system[Wikipedia:Pronephros]. // TODO - check developmental relationships. Note that we previously include the ZFA/XAO terms under the more specific 'pronephric kidney', but these are now merged. TODO GCI: relationship: capable_of GO:0030104 UBERON:0005794 MAT:0000117 UMLS:C0231048 SCTID:308804007 MIAA:0000117 ZFA:0000151 EMAPA:16579 XAO:0002000 EHDAA:1017 FMA:72170 EHDAA2:0001570 EFO:0000927 NCIT:C34280 MESH:D060910 VHOG:0000037 AAO:0011089 BTO:0001541 Wikipedia:Pronephros TAO:0000151 pronephric kidney pronephron archinephron embryonic kidney UBERON:0002120 In mammals, the pronephros is the first of the three embryonic kidneys to be established and exists only transiently. In lower vertebrates such as fish and amphibia, the pronephros is the fully functional embryonic kidney and is indispensible for larval life[GO]. The embryonic kidney, present at the level of the third somite, is composed of two glomeruli fused at the midline, two pronephric tubules, and paired bilateral pronephric ducts that modify the composition of the blood filtrate before delivering it to the cloaca for excretion.Kimmel et al, 1995.[TAO] A kidney formed of nephric tubules arising in the anterior region of the nephric ridge; forms only as a transient embryonic structure. [Evolution, Fourth_Edition_(2006)_McGraw-Hill, Function, Kardong_KV, Vertebrates:_Comparative_Anatomy, p.748][VHOG] Organ that serves as a transient kidney, providing osmoregulation during early developmental stages and then degenerating during metamorphosis.[AAO] In all vertebrate embryos, the kidney begins with the differentiation of a few renal tubules from the anterior end of the nephric ridge overlying the pericardial cavity. (...) This early-developing embryonic kidney is called the pronephros.[well established][VHOG] pronephric located_in located in located in located_in (type level) develops_from develops from develops from kidney intraembryonic coelom mesoderm-derived structure kidney rudiment developing anatomical structure pronephric mesoderm rostral part of nephrogenic cord