Confocal micrograph of a colonic crypt in cross section. Mucin cells (red) in the crypts produce mucous which passes into the interior of the colon through crypt lumen (the area in the centre surrounded by blue) to facilitate the movement of the faecal mass through the colon. Staining for F- actin (green) shows the pericryptal sheath. This tissue is from an endoscopic colonic biopsy for a child and shows the normal appearence of a crypt.