Uterus endometrium. Coloured Scanning Electron Micrograph (SEM) of the surface epithelium (endometrium) of the human uterus. The exposed epithelial cell surfaces are covered in numerous microvilli. The endometrium containing openings to tubular uterine glands beneath the epithelial surface.The glands are embedded in abundant collagen and reticular fibres of stroma connective tissue. After ovulation the glands become active and secrete substances to nourish the fertilised egg. Magnification: x600 when printed at 10 cm wide