Kidney always so simple; in cartilaginous fish and some amphibians, there is also a shorter duct, similar to the amniote ureter, which drains the posterior (metanephric) parts of the kidney, and joins with the archinephric duct at the bladder or cloaca. Indeed, in many cartilaginous fish, the anterior portion of the kidney may degenerate or cease to function altogether in the adult. In the most primitive vertebrates, the hagfish and lampreys, the kidney is unusually simple: it consists of a row of nephrons, each emptying directly into the archinephric duct. Invertebrates may possess excretory organs that are sometimes referred to as
Bladder tank Bladder tank A bladder tank is a large, flexible container used to store many types of liquids. When maximum capacity is reached, the bladder tank takes the form of a large pillow, hence it is also called a pillow tank. The first flexible bladder tank was constructed out of polyester and PVC in Alger (Africa) in the 1950s. It was invented by André Labaronne (patent N°1.460.825, 19 October 1965) and marketed under the brand CITAF (Citernes pour l’agriculture Française). Flexible bladder tanks are made with high resistance PVC material and are welded with high frequency (HF) soldering techniques. The bladder