Capillaries of the gall bladder. Coloured Scanning Electron Micrograph (SEM) of blood vessels lining the wall of the gall bladder. Here, a rich network of fine capillaries is seen (pink) branching off a blood vessel (grey). Beneath this network are a number of larger blood vessels (blue). This vascular system occurs in the submucosal layer of the gall bladder. Blood and lymphatic vessels serve to drain water reabsorbed from bile during bile formation. The gall bladder is a muscular sac, attached to the liver, which collects and concentrates bile, a substance which aids in fat digestion. Magnification: x100 at 6x7cm size. Magnification: x125 at 4x5 inch size.