Cervical cancer cells, coloured scanning electron micrograph (SEM). The cervix is the lower part of the womb, also called the neck of the womb and comprises part of the woman's reproductive system. Cervical cancer is more common in younger women and one of the main causes is a persistent infection of certain types of the human papilloma virus (HPV). In this image the central cell is displaying blebbing. Blebbing is a bulge or protrusion of the plasma membrane of the cell which is visible on the cell surface. Blebbing may occur for a number of different reasons including during apoptosis, if a cell is undergoing physical or chemical stress. It also has important functions in cellular processes such as cell locomotion, playing a role in cell migration. Magnification: x3100 when printed at 10cm wide.