Cervical smear test. Light micrograph of a cervical smear containing normal squamous epithelial cells and numerous spermatozoa. The squamous cells are stained red and blue, and have large nuclei. The spermatozoa have small dark heads and long tails. Cervical smear tests are performed to check for abnormalities in the cells of the uterine cervix, which may indicate the onset of cancer. During sexual intercourse spermatozoa are deposited near the cervix, from where they will attempt to reach an egg to fertilize it. Magnification: x1150 when printed 10cm wide.