Kidney Kidney The kidneys are two bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder. The nephron is the structural and functional unit of the kidney. Each adult kidney contains around 1 million nephrons. The nephron utilizes four processes to alter the blood plasma which flows to it: filtration, reabsorption, secretion, and excretion. The
Bladder stone and extract bladder stones. Celsus gave the first description of lithotomy as performed before and during his time, and the operation has ever since borne his name—the Celsian method. Lithiasis (stone formation) in the bladder is called cystolithiasis (), from "cysto-" (bladder/cyst) + "-lith" (stone) + "-iasis" (disorder). Bladder stone A bladder stone is a stone found in the urinary bladder. Bladder stones are small mineral deposits that can form in the bladder. In most cases bladder stones develop when the urine becomes very concentrated or when one is dehydrated. This allows for minerals, such as calcium or magnesium salts,