Physiological anatomy of the kidneys and urinary system

The kidneys are located on the posterior wall of the abdominal cavity, outside the peritoneum. Each adult kidney weighs about 150 grams and is about the size of a fist. The middle surface of each kidney contains an indented area called the umbilical cord through which the kidney artery and veins, the lymphatic, supply the nerves and ureter, which carries urine eventually from the kidney to the bladder, where It is stored until the bladder is empty. The kidneys are surrounded by sclerenchyma, protecting its delicate internal structures.

If the kidney is divided from top to bottom, the two main regions that can be visualized are the outer cortex and the inner medullary region. The marrow is divided into 8 to 10 conical masses called the pyramid. The base of each pyramid originates from the border between the shell and the marrow and ends at the papillae, shining into the space of the renal pelvis, a funnel-shaped connection of the upper end of the ureter. The outer contour of the pelvis is divided into open pockets called large calyxes that extend downwards and into small stations, which collect urine from the tubes of each papilla. The walls of the calyx, pelvis and ureter contain contractile elements that push urine toward the bladder, where urine is stored until it is emptied by urination.

Figure. Organization of the kidneys and urinary system.