Blood glucose

• If concentration of glucose in the blood decreases below a certain level

  Cells may not have enough glucose for respiration and may not function normally
• If concentration of glucose increases above a certain level

  Can also disrupt normal function of cells
• The control of blood glucose concentration is a key part of homeostasis
• Blood glucose concentration control

  • Controlled by two hormones
  • Secreted by the endocrine tissue in the pancreas
• This tissue is made up of groups of cells known as the islets of Langerhans
• Cell types in islets of Langerhans

  • A cells
  • B cells
• A cells

  Respond by secreting Glucagon
• B cells

  Respond by stopping secretion of insulin
• A and B cells act as the receptors and initiate the response for controlling blood glucose concentration
• The control of blood glucose concentration by Glucagon can be used to demonstrate principles of cell signaling