All moral rights asserted. Recolouring or alteration of the image is prohibited without permission. Coloured scanning electron micrograph (SEM) of a freeze fracture of a human amniotic membrane, which encloses the foetus in the womb (uterus). At top is the epithelium (pink) the inner layer of the amnion. Next is the compact layer (brown), which is acellular and formed of reticular fibres made of collagen, followed by the fibroblast layer (yellow), which secretes collagen. The outer layer is the extraembryonic coelom, or spongy layer (grey), which is gelatinous and protein-rich. Magnification: x1200 when printed at 15 centimetres wide.