Colon lining. Coloured light micrograph of a section through a human colon. The colon is lined with intestinal villi containing crypts of Lieberkuhn, elongated pockets (lower right) that lie in the vascular submucosa (white) . These glands contain two types of cells: goblet cells (pink), which secrete a lubricant into the colon which aids the movement of faeces; and absorptive columnar epithelial cells (purple), which absorb water from the faeces. The number and shape of the glands greatly increases the surface area for absorption. Magnification: x500 when printed 10cm wide.