Homeostasis

• What happens when blood glucose levels drop?

  Alpha cells in the pancreas detect the fall in blood glucose concentration

  Glucagon is released resulting in glycogenolysis: glycogen to glucose andnd gluconeogenesis occurs where non-carbohydrate molecules like amino acids are converted into glucose, all in the liver .

  The glucose made then diffuses into the blood increasing blood glucose concentration back to normal levels which prevents more glycogen from being made.
• What organs is responsible for the maintenance of blood glucose levels?

  Pancreas and liver
• What role does the pancreas play in blood glucose regulation?

  when blood glucose is low:

  • alpha cells detect low blood glucose concentration
  • the hormone glycogen is released and binds to receptors on fat and liver cells
  • Induces glycogenolysis and gluconeogenesis

  when blood glucose is high:

  • Beta cells detect high blood glucose concentration
  • The hormone insulin is secreted
  • insulin binds onto receptors on cells which open protein channels which insulin then enters through and activates enzymes to convert glucose into glycogen (glycogenesis)
• What role does the liver play in blood glucose concentration?

  Site where glucagon binds and induces gluconeogenesis and glyconolysis
• Uses of urine samples?

  • Pregnancy tests
  • medical diagnoses
  • drug tests
• Route of excretion in the kidney?

  1. Renal artery
  2. afferent and efferent artereole
  3. glomelulus
  4. bowman's capsule
  5. Proximal convoluted tubule
  6. loop of henle
  7. Distal convoluted tubule
  8. collecting duct
• Gluconeogenesis is the process of converting non-carbohydrate molecules into glucose
• Adaptations of the proximal convoluted tubule (PCT) in the kidney?

  Mitochondria to produce ATP for active transport

  Large number and variety of transport proteins

  Microvilli to increase surface area for diffusion

  short diffusion distance for one cell
• Identify this region of the pancreas

  Contains alpha cells that detect when blood glucose levels get too low

  Contains Beta cells that detect when blood glucose levels get too high

  A) Islets of Langerhans

  
• How is glucagon used to regulate blood glucose concentration?


  Alpha cells in the pancreas detect low blood glucose concentration and secrete glucagon which travels through the blood stream binding onto fat, muscle and liver cell receptors to stimulate glycogenolysis, the breakdown of glucagon into glucose.

  Glucagon inhibits insulin secretion

  Glycogen also stimulates gluconeogenesis in the liver.

  Theres a negative feedback look in place in case then when blood glucose concentration returns to normal or gets too high, glucagon secretion is inhibited
• What causes type 1 diabetes?

  pancreas unable to produce enough insulin, maybe due to a genetic defect or disease

  Islets of langerhans are damaged or destroyed maybe due to an autoimmune disease