Light micrograph of normal urothelium (the normal lining of the bladder and urinary tract). This urothelium has particularly prominent umbrella cells, which are the cells with many white vacuoles (look like bubbles). The umbrella cells function to protect the urothelial cells by covering them when the bladder stretches when it is filled with urine. Haematoxylin and eosin stained tissue section. Magnification: 200x when printed at 10 cm.