Uterus endometrium. Colour scanning electron micrograph of the heavily-folded internal surface of the human endometrium, the mucosal lining of the uterus, taken at the mid secretory stage (around the 20th day of menstrual cycle). The endometrium consists of a ciliated epithelium supported by a highly cellular connective tissue stroma containing many tubular glands. After ovulation (the release of the egg from the ovary) & under the influence of the hormone progesterone, these glands secrete glycogen, mucous & lipids to provide a moist & hospitable environment for the potential implantation of a fertilised egg. Magnification: x300 when printed at 10 cm wide.