Kidney glomerulus. Coloured scanning electron micrograph (SEM) of a blood vessel (green, bottom right) running into a glomerulus (blue & green) in the human kidney. Glomeruli are made up of a tight knot of blood capillaries covered in podocyte cells. These tiny filtration units remove toxic waste products from the blood. The filtered fluid then drains to the bladder as urine. Magnification unknown.