Caption

Light micrograph of normal human pancreas, showing a section through an Islet of Langerhans. The pancreas is a gland secreting both externally (digestive juice) and internally (insulin and other blood regulatory substances). Here the exocrine tissue is the red stained background, in which appears an Islet of Langerhans, the source of endocrine secretion. Two cell types are visible in the Islet; A cells (red) and B cells (purple). The meshwork of blue and white in the Islet represents the system of blood capillaries, into which the endocrine secretions are discharged. Magnification x50 at 35mm size.