Kidney capillary. Coloured scanning electron micrograph (SEM) of a fracture through a glomerular capillary. A kidney glomerulus, which filters waste products from the blood, consists of a coiled mass of capillaries surrounded by a capsule. The lumen wall of the glomerular capillaries consists of fenestrated epithelium (yellow), that is epithelium with many pores. These pores, or fenestrae, allow water and small solutes, but not larger molecules, to filter out of the blood into the capsule. After the reabsorption of certain substances elsewhere in the kidney the liquid is transported to the bladder as urine. Magnification: x15,000 when printed at 10 centimetres wide.