Stock Photo - ANATOMY, URINARY TRACT<BR>Model of the internal anatomy of the trunk of an adult human body of indeterminate sex, anterior view. The deep organs can be seen here thanks to the removal of both the digestive system (liver, gallblader, stomach, pancreas, intestines) and the reproductive organs. A portion of the rectum (brown) appears in frontal section under the sacral promontory (hip bone, off-white with pale blue stripe). The spleen (mauve) is located laterally against the abdominal wall. The kidneys filter the blood that they receive from the renal artery (red), a branch of the abdominal aorta, producing urine, which is then collected in the renal pelvis (central structure of the kidney, beige), and carried by the ureters (beige ducts) to the urinary bladder (shown in frontal section, flesh-colored). The filtered blood is next drained by the renal vein (blue), which empties into the inferior vena cava. The right kidney is shown in frontal section, exposing its internal anatomy. It is composed of the cortex (pinkish superficial area) and the medulla, which includes several malpighian pyramids (red) separated by the renal columns. The top of each pyramid, called the papilla, leads to a calyx (cup-shaped white structure) that collects the urine and pours it out into the renal pelvis. Vascular tissue is present in the cortex and renal columns. The renal sinus is a cavity projecting from the hilus and containing fat (in yellow). The kidneys are surmounted by the hormone-secreting adrenal glands (orange). The urinary bladder wall is mainly composed of the bladder muscle (pink), the contraction of which allows urine evacuation. The internal wall of this muscle is covered by a mucous membrane (flesh-colored) with many folds. The abdominal aorta (red) divides into the right and left common iliac arteries, then into the external iliac arteries in the pelvis to irrigate the lower limbs. It ramifies in order to vascularize the abdominal organs, such as the renal arteries for the kidneys, and the genital arteries (ovarian in women and testicular in men) running alongside the external iliac arteries and carrying oxygenated blood to the reproductive organs. In parallel, the external iliac veins (blue), draining the lower limbs, empty into the common iliac veins, which join up to form the inferior vena cava carrying deoxygenated blood towards the heart. The inferior vena cava also receives blood from numerous abdominal veins, such as the renal and genital veins, adjoining the arteries with the same names. The muscles (flesh-colored) covering the abdominal wall appear in the background.