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
Celiac artery cannot be safely ligated in a living person, and obstruction of the celiac artery will lead to necrosis of the structures it supplies. The celiac artery is the only major artery that nourishes the abdominal digestive organs that does "not" have a similarly named vein. Most blood returning from the digestive organs (including from the area of distribution of the celiac artery) is diverted to the liver via the portal venous system for further processing and detoxification in the liver before returning to the systemic circulation via the hepatic veins. In contrast to the drainage of midgut and hindgut structures