part of part of develops from develops from renal glomerulus pronephros pronephric glomerulus SCTID:360548001 a glomus differs from a glomerulus in that each vascular glomus services several tubules UBERON:0004191 Paired highly vascularized portion of the pronephros. Left and right glomeruli are fused at the midline. Begins to function between 40 and 48hpf. Drummond, 2000.[TAO] The teleost pronephros shares many essential features with the amphibian pronephros including its derivation from mesoderm associated with the coelom and the derivation of the glomerular blood supply from the medial dorsal aorta. However, unlike the pronephros of amphibians, which have an external glomus and tubules with nephrostomes open to the coelom, the mature teleost pronephros has no connection to the body cavity and instead functions as a closed system (reference 1); This variation in nephron types [with external glomeruli that open into the coelom and with internal glomeruli that do not connect with the coelom] and their pattern of distribution suggest an evolutionary sequence. Ancestral craniates probably had an external glomerulus and nephrostomes, as do the first few to develop in very primitive craniates. (...) The mechanism would become more efficient as the coelomic recess into which each glomerulus discharged became a part of the tubule, that is, grew around the glomerulus as a renal capsule. The glomerulus becomes internal. The nephrostomes were lost during subsequent evolution, leaving the type of renal tubule found in most vertebrates (reference 2).[well established][VHOG] GO treats glomus and pronephric glomerulus differently glomera pronephric glomera XAO:0000318 corpuscle The glomus forms from the splanchnic intermediate mesoderm and is the vascularized filtration unit, filtering the blood before it enters the tubules. The glomus is external to the nephron and extends over more than one body segment. UBERON:0004739 pronephric glomus ZFA:0001557 TAO:0001557 VHOG:0001237 glomus AAO:0011049 glomerulus of pronephros pronephric glomeruli glomeral mesenchyme