Pancreas

• what is the endocrine function?


  Islets of Langerhans produce insulin and glucagon
• what is the exocrine function?

  Acini cells produce digestive enzymes, duct cells secrete sodium hydrogencarbonate (aq)
• connected to duodenum to remove digestive enzymes

  • amylases, lipases, proteases (trypsinogen)
• what are the types of Islets of Langerhans


  • alpha (⍺) cells produce and secrete glucagon, more ⍺ than β
  • beta (β) cells produce and secrete insulin
• insulin


  • secreted from β cells, which detect when blood glucose concentration too high
  • target cells are: hepatocytes (liver), muscles cells and other body cells, like the brain
  • is a second messenger
• glucagon


  • secreted by ⍺ cells, which detect when blood glucose concentration is too low
  • target cells are hepatocytes
• why is glucagon target the liver


  glucose is stored as glycogen in the liver, so needs to be converted (hydrolysis) then released
• function of insulin


  1 - binds to receptors

  2 - changes membrane shape

  3 - stimulates a cascade (don't need to know)

  4 - glucose channels open

  5 - glucose enters cell

  6 - blood glucose concentration decreases
• how do cells appear in microscopes (histology)


  Acini cells appear darker, Islets of Langerhans appear lighter