The Endocrine part of the Pancreas is the Islets of Langerhans which contain alpha and beta cells. These cells secrete hormones directly into the blood. The alpha cells secrete glucagon and the beta cells secrete Insulin.The Exocrine part of the pancreas is a gland containing Acinar cells. Acinar cells secrete substances into ducts, such as digestive enzymes and bicarbonate. These substances are transported in vesicles and the vesicles deposit the substances where they are required throughout the body.