Renal Anatomy

The kidneys are a pair of fist sized organs located in the small of the back behind the peritoneum. Each kidney weighs about 115g-170g and have the following approximate dimensions: 11 cm in length, 6 cm in width, and 3 cm thick - about the size of a deodorant stick.[3] 
 
 


Source: Fox S.I., Human Physiology 6th edition, pg. 528 Each kidney is perfused at a rate of 600 ml/min by way of the renal artery [3]. Each renal artery branches into interlobar arteries, arcuate arteries, interlobular arteries, and then into 1.2 million afferent arterioles that each feed each nephron, the functional unit of the kidney. After blood has been filtered through the glomerulus and transported through the nephron's vasculature it passes through the interlobular, arcuate, and interlobar that merge into the renal vein and back in to systemic circulation. [2]
The kidney is composed of two regions, the renal cortex and medulla. The cortex is where the renal corpuscles reside, proximal tubules, and distal tubules are found. The medulla is home to the loop of Henle, vasa recta, and collecting tubules. Urine from the various collecting ducts drains into the renal pelvis, ureter, and bladder.