This is a photograph of a human kidney viewed with the scanning objective (4x). It was taken with a Samsung SH100 digital camera through the eyepiece of a compound microscope. This image shows a good overview of the cortex of a kidney. In the top left corner and bottom right corner, straight segments called medullary rays can be seen. These rays section the kidney cortex into cortical labyrinths which are essentially the structural units of the kidney cortex and contain many nephrons. In this image cross sections of blood vessels can also be seen. Another feature that defines this image as coming from the renal cortex is the presence of proximal and distal tubules. At this magnification the tubules cannot be differentiated but at higher power one can see the difference. Finally, about eight renal corpuscles are visible in this image. Within the corpuscle is a mass of fenestrated capillaries, the glomerulus, which is the filtration unit of kidney.