Question

Choose between the two options to answer the question specified in the brackets for the following. An example is illustrated.
Example: Corolla or Calyx (Which of the outer whorl?)

Answer 1

A short paired artery that emerges from the lateral part of the aorta is the renal artery. It is found in the retroperitoneum, where the renal veins, nerves and pancreas run laterally towards the hilum of the kidney posterior to it. Before dividing into its terminal anterior and posterior branches in the hilum of the kidney, the renal artery gives off numerous tiny branches.

Complete answer:
The function of the renal artery is twofold; it provides oxygenated blood to the kidney parenchyma, and at the same time delivers the blood to be recycled by eliminating metabolic waste and excess water and reabsorbing minerals and nutrients. The renal artery emerges perpendicularly from the abdominal aorta just below the superior mesenteric artery branching, roughly at the level of the artery.

The right renal artery, slightly longer and slightly higher than the left renal artery, follows the inferior vena cava, the renal vein, the pancreas head, and the second portion of the duodenum. The left renal artery flows to the renal vein, the pancreatic body, and the splenic vein more horizontally and posteriorly. The renal artery most prominently gives off one or more inferior suprarenal arteries during its extra-arenal course. Additionally, for the ureter, perinephric tissue, renal capsule and renal pelvis, the renal artery gives off some unidentified branches.

The renal vein is an asymmetrically coupled artery that transports deoxygenated blood to the inferior vena cava from the kidney. Both the left and right veins flow anterior to the renal arteries they correspond to. The right renal vein only receives tributaries from the kidney, while multiple tributaries from other organs, including the left gonadal (ovarian / testicular) vein, left inferior phrenic vein, and left adrenal vein, are obtained by the left renal vein.

The renal artery brings blood to the kidney, while blood is carried away from the kidney by the renal vein. As the blood is filtered by the kidney, the renal vein carrying blood has a lower concentration of urea than the renal artery.

Hence, the correct answer is option (B).

Note: The proximal part of the right renal artery is anteriorly connected with the inferior vena cava, while the distal part is connected with the shorter right renal vein. It is isolated from the second part of the duodenum and pancreas head by these structures. There is a renal vein for each kidney.