Endocrine Pancreas S2M1

  1. What percent of the pancreas is endocrine compared to exocrine
    • 1% Endocrine
    • 99% Exocrine
  2. Hypoglycemia for an extended period of time can have what effects
    • Neurological problems
    • Coma
    • Quick Death
  3. What is considered hyperglycemic and hypoglycemic
    • Hyper - Glucose above 110mg/100mL
    • Hypo - Glucose below 60mg/100mL
  4. What are the major types of nutrient substances
    • Carbohydrates
    • Fats
    • Proteins
  5. Where are most of the carbohydrates and fats eventually excreted
  6. What substrates are metabolized directly for energy
    Carbohydrates and fats
  7. What tissues are involved in substrate interconversions
    • Adipose tissue
    • Liver
    • Muscle
    • Kidney
  8. What systems are the interconversion of substrates regulated by
    • Endocrine system
    • Sympathetic Nervous system
  9. How long do the absorptive and Post absorptive states last, and what are their main sources of energy
    • Absorptive - 60min (Glucose is main energy source)
    • Post Absorptive - 2+ hours (Fat is the main source)
  10. What factors regulate insulin release from pancreatic beta cells
    • GI hormones (+)
    • Increase in amino acids (+)
    • Increase in Glucose (+)
    • Parasympathetic nervous system (+)
    • Sympathetic nervous system (-)
  11. What cells secrete insulin
    Beta cells in the pancreas
  12. How does an insulin secretion curve present over sixty minute period following a meal
    There is an initial spike of insulin in the blood as a result of the stored insulin released, then a significant dip followed by a gradual increase as a result of synthesis of new insulin
  13. What is the sequence that leads to insulin release following glucose uptake
    • GLUT2 glucose transporter shunts glucose into the B cell
    • Glucokinase phosphorylates the glucose to Glucose 6-P
    • Glycolysis converts the Glucose 6-P into ATP
    • ATP stops the K+ channel causing depolarization of the cell
    • Calcium channels open filling the cell with Ca+
    • Calcium channels cause the bursting of the insulin storage granules releasing insulin into the blood
  14. How do GLUT1, 2, and 4 differ
    • GLUT1 - Found in the brain (insulin sensitive)
    • GLUT2 - Found in liver beta cells (not sensitive to insulin)
    • GLUT4 - Found in adipose tissue, and muscle (insulin sensitive)
  15. What is unique about insulin transport in the blood
    It is a water soluble peptide and therefore doesn't require transporters to carry it
  16. What receptor mechanism does insulin activate once it binds
    Tyrosine kinase to initiate cellular responses
  17. Insulin has what effect on GLUT4
    When insulin receptors are activated, they recruit GLUT4 transporters from vescicles in muscle and adipose tissue
  18. Lipoprotein Lipase (LPL) synthesis, activity, and movement to the surface of endothelial cells is activated by
    Insulin stimulation on the Adipose cells GLUT4 receptor
  19. What actions does insulin have on muscle cells
    • It recruits GLUT4 receptors from vesicles and increases;
    • Protein synthesis /Decrease degradation
    • Amino acid uptake
    • Glycogen synthesis
    • Glucose transport
    • Decrease in Glycogenolysis
  20. What kind of glucose receptors are on hepatocytes
    GLUT2 (not insulin sensitive)
  21. What is the action of insulin on the hepatocytes
    • Shuts off Gluconeogenesis, Glycogenolysis, and lipolysis
    • Increases Lipogenesis, and glycogen synthesis
  22. What is the effect of insulin on adipose tissue
    • A decrease in Glycogenolysis, and Lipolysis
    • Increase in Glucose transport, Glycogen synthesis, Lipogenesis
  23. Glycogenolysis
    Coversion of glucogen to glucose stimulated by Glucagon or Epinephrine
  24. Ketogenesis
    Process of making ketone bodies from the breakdown of fatty acids
  25. What is the net result of insulin on Lipid metabolism in the blood
    A decrease in both plasma free fatty acids and ketogenesis (ketones in the blood)
  26. What is the net result of insulin on Protein metabolism in the blood
    Decrease in plasma amino acids and urinary nitrogen creating a positive nitrogen balance
  27. Alpha cells in the pancreas secrete
  28. What causes the release of glucagon
    • A decrease the plasma glucose
    • An increase of amino acids in plasma
  29. What is the general action of Glucagon on adipose tissue
    Increase in lipolysis
  30. What is the effect of Glucagon on the liver
    Increase in; Lipolysis, Gluconeogenesis, Glycogenolysis
  31. What is the effect of Glucagon on pancreatic Beta cells
    Increase in the release on insulin (indirectly)
  32. What is the cellular response in the liver to Glucagon
    • G cell receptor is activated
    • Adenylyl cyclase is stimulated
    • cAMP is formed
    • Phosphorylase b is converted to its active form "a"
    • Glycogenolysis and Gluconeogenesis take place
  33. What is the cellular response of adipose tissue to Glucagon
    • G cell receptor activated
    • Adenylyl cyclase stimulated
    • cAMP formed
    • PKA activates lipase
    • Lipolysis begins
  34. What happens to the levels of Glucagon and insulin after a meal
    Glucagon lowers and Insulin elevates
  35. Epinephrine release in regard to energy metabolism is stimulated when
    • Stress
    • Acute hypoglycemia
  36. What is the effect of stress and hypoglycemia on energy metabolism
    It increases the amount of epinephrine which stimulates Glucagon release, Gluconeogenesis, Glycogenolysis, Lipolysis, and has an indirect inhibition on insulin secretion
  37. Cortisol has what effect on energy metabolism
    • Gluconeogenesis (liver)
    • Lipolysis (adipose tissue)
    • Protein catabolism
  38. What effect does Leptin have on energy metabolism
    • It directs storage of excess caloric intake into adipose and thus supports insulin
    • Supports reproduction, erythropoiesis, and lymphopoiesis
  39. Incretins
    Peptide hormones that augment insulin secretion 3-4 times then that of the un-augmented state
  40. How do Incretins work
    Increases cAMP and PKA levels in beta cells increasing Ca++
  41. Incretin augmentation can be lost in those with
    Diabetes type II
  42. Glucose-dependent insulinotropic polypeptide (GIP) and Glucagon-like peptide 1 (GLP1) are what
    The primary hormones that act as Incretins
  43. Acute starvation has what net effect in the blood
    • Glycogen depletion
    • Increase in plasma free fatty acids
    • Increase in Ketones
    • Negative N2 balance (protein loss)
  44. Stress and Exercise has what net metabolic effect
    • Decrease in Triglyceride synthesis
    • Increase in Glycogenolysis, Gluconeogenesis and Lypolysis
  45. What are the physical signs of Hypoglycemia
    • Head issues (headache, confusion, tiredness)
    • Speech issues
    • Heart issues (tachycardia)
    • Hunger
    • Hands cold, sweating, and trembling
  46. What are the two types on Diabetes Mellitus
    • Type 1 - Impaired insulin production due to damage to Beta cells
    • Type 2 - Inadequate action of insulin on insulin receptors
  47. What are some important signs of Diabetes Mellitus
    • Plasma Glucose above 125mg/dL
    • Glucosuria and Polyuria
    • Acetone Breath
  48. What happens to the metabolism of carbohydrates in insulin deficiency
    • Decrease in Glucose uptake and Glycogenesis
    • Increase in Gluconeogenesis and Glycogenolysis
    • This causes Hyperglycemia, Glucosuria, Polyuria, Dehydration, and eventual circulatory collapse
  49. What is the effect of insulin deficiency on Lipid metabolism
    • Decrease in Lipogenesis
    • Increase in Lipolysis
    • Causing Hyperlipidemia, Ketogenesis, Ketonemia, Ketouria, Metabolic acidosis
  50. What is the effect of insulin deficiency on protein metabolism
    • Decrease in amino acid uptake and protein synthesis
    • Increase in protein degredation
    • Causing Aminoacidemia, increase in nitrogen excretion, and (-) nitrogen balance
Card Set
Endocrine Pancreas S2M1