Pancreatic Hormones

Endocrine secretion takes place in the bloodstream. Exocrine as the opposite function is the excretion mode of glands or gland cells which secrete their secretions to external (skin) or internal surfaces (intestinal lumen, urogenital tract). The arrangement of these cells in groups diffusely scattered throughout the gland is reminiscent of islands under the microscope. Most frequently, the approximately 1 million islands are to be found in the rear part (pancreas-tail).