Hematosalpinx. Coloured scanning electron micrograph (SEM) of a freeze-fractured of a fallopian tube. Hematosalpinx is the accumulation of blood in fallopian tubes. Its most common cause is ectopic pregnancy, but the other causes include pelvic inflammatory disease (PID), endometriosis and pelvic trauma. Fallopian tubes are ducts that lead from the ovaries to the uterus. The epithelium consists of columnar cells, many of which have cilia (purple). The cilia beat is towards the uterus, aiding transport of the egg from the ovary. Coloured blue are the secretory cells with their microvilli projections and mucous secretion. These cells secrete a substance that maintains a moist environment in the tube and may provide nutrients for the egg. Magnification: x2000 when printed at 10 centimetres wide.