control of blood glucose levels

• What cells produce insulin

  beta cells
• what cells produce glucagon

  alpha cells
• where are beta and alpha cells from

  islets of langerhans
• what is secreted if blood glucose levels are too high

  insulin
• what is secreted if blood glucose levels are too low

  glucagon
• what does insulin do

  makes the liver more permeable to glucose, where enzymes then convert it into glycogen
• define glycogenesis 


  process of excess glucose being converted too glycogen in the liver
• define glycogenolysis 


  glycogen is broken down into glucose in the liver when blood glucose levels are too low
• define gluconeogenesis 


  glucose is made from non-carbohydrates stored in the liver (amino acids). Occurs when all glycogen has been converted to glucose but glucose levels are still too low
• how does insulin decrease blood glucose levels

  • attaches to receptors on target cells (liver cells) which stretches (changes tertiary structure) of channel proteins too widen, increase SA more glucose diffuse in by FD
  • more channel proteins incorporated onto cell surface membrane, increase surface area, more glucose diffuse into liver via FD
  • KEY MARKING POINT (insulin binds to receptors causing chemicals to be released, where vesicles carrying glucose channels then fuse with the CSM
  • finally, when beta cells bind to receptors on liver cells, activates glycogenesis
• glycogen is insoluble
• Describe the second messenger model (glucose levels too low)

  • glucagon binds to receptors on target cells
  • activates protein to change shape to the enzyme, adenyl cyclase
  • which then converts ATP to cAMP
  • cAMP then activates protein KINASE enzyme for glycogenolysis
  • and glycerol/amino acids into glucose
• Describe second messenger model for adrenaline

  • adrenaline binds to receptors
  • G protein activated and converts ATP too cAMP
  • cAMP then activates an enzyme to hydrolyse glycogen into glucose
• what is type 1 diabetes

  body unable too produce own insulin from childhood, can be a result of an autoimmune disease, where own bodies Beta cells are attacked, meaning they can no longer secrete insulin or cannot detect the changes in glucose levels
• What is type 2 diabetes

  Receptors, on the target cells, lose responsiveness too insulin, - adults most commonly, due too obesity and poor diet, can be regulated by exercise and reduce carbohydrate intake