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
Urinary incontinence pressure falls and bladder pressure rises. The body stores urine — water and wastes removed by the kidneys — in the urinary bladder, a balloon-like organ. The bladder connects to the urethra, the tube through which urine leaves the body. During urination, detrusor muscles in the wall of the bladder contract, forcing urine out of the bladder and into the urethra. At the same time, sphincter muscles surrounding the urethra relax, letting urine pass out of the body. Incontinence will occur if the bladder muscles suddenly contract (detrusor muscle) or muscles surrounding the urethra suddenly relax (sphincter muscles). Urination, or