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
Pneumatic bladder cargo within a container. Pneumatic bladders are used in medical research. Leading edge inflatable kites use pneumatic bladders restrained by a fabric case; the bladder is selected slightly larger than the case, so that at operational inflation the bladder is not stressed while the case defines the final shape of the leading edge. Many of the wing's airfoil ribs are similarly bladdered. Pneumatic bladder A pneumatic bladder is an inflatable (pneumatic) bag technology with many applications. Pneumatic bladders are used to seal drains and ducts to contain chemical spills or gases. Pneumatic bladders are often used for the containment of