Blood sugar level several interacting systems, of which hormone regulation is the most important. There are two types of mutually antagonistic metabolic hormones affecting blood glucose levels: These hormones are secreted from pancreatic islets which are bundles of endocrine tissues. There are four types of pancreatic islets, alpha (A) cells, beta (B) cells, Delta (D) cells and F cells. Glucagon is secreted from alpha cells, while insulin is secreted by beta cells. Together they regulate the blood-glucose levels through negative feedback, a process where the end product of one reaction stimulates the beginning of another reaction. In blood-glucose levels, insulin lowers the concentration
Organ procurement organization Organ procurement organization In the United States, an organ procurement organization (OPO) is a non-profit organization that is responsible for the evaluation and procurement of deceased-donor organs for organ transplantation. There are 58 such organizations in the United States, each responsible for organ procurement in a specific region, and each a member of the Organ Procurement and Transplantation Network (OPTN), a federally mandated network created by and overseen by the United Network for Organ Sharing (UNOS). The individual OPOs represent the front-line of organ procurement, having direct contact with the hospital and the family of the recently deceased donor. Once