Brunner, Johann Conrad (1653–1727), Swiss anatomist. Brunner is known for his work on the pancreas and duodenum. In 1683 he made pioneering experimental excisions of the spleen and pancreas in dogs and noted the resultant extreme thirst and polyuria. In 1672 he discovered the glands of the duodenum that bear his name and published a report on them in 1688. He believed that the glands secreted a juice similar to that of the pancreas and that they played a chief role in intestinal digestion.