Lactating breast tissue. Coloured scanning electron micrograph (SEM) of a section through tissue from a mammary gland, or breast. Several alveoli (green) are seen emptied of the milk that they produce. The secretions are collected in the alveolar ducts (pink) that eventually lead to the nipple. The ducts are separated by loose, highly vascular connective tissue (brown). Magnification: x100 at 6x7cm size.