Light micrograph of Brunner??? glands in a human duodenum (the first part of the small intestine). The Brunner??? glands secrete mucus which is alkaline, thus helping neutralize acid from food that enters the small intestine from the stomach. The Brunner??? glands each include several cells which have small round nuclei, seen as the dark dots lining each of the tubular shaped or branching glands. Most of the volume of the Brunner??? glands cells is made up of mucin, which has a light blue-purple colour. The pink substance surrounding each of the glands is fibrous or connective tissue which functions to hold all the component cells together. Haematoxylin and eosin stained tissue section. Magnification: 200x when printed at 10cm.