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
Inferior rectal artery Inferior rectal artery The inferior rectal artery (inferior hemorrhoidal artery) is an artery that supplies blood to the lower half of the anal canal. The inferior rectal artery arises from the internal pudendal artery as it passes above the ischial tuberosity. Piercing the wall of the pudendal canal, it divides into two or three branches which cross the ischioanal fossa, and are distributed to the muscles and integument of the anal region, and send offshoots around the lower edge of the gluteus maximus to the skin of the buttock. They anastomose with the corresponding vessels of the opposite side, with