Human Physiology Final - Glucose Homeostasis

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Human Physiology Final - Glucose Homeostasis
2014-05-04 20:26:27
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  1. (Anabolic/Catabolic) pathways predominate during the absorptive state
  2. Major hormones during absorptive state
    • Insulin
    • Growth hormone
  3. (Anabolic/Catabolic) pathways predominate during the post absorptive state
  4. The majority of ingested CHO is digested and absorbed in ______________________
    Upper 20% of small intestine
  5. Digestion of CHO begins where?
    Mouth (salivary amylase)
  6. 3 Glut transporters expressed in GI epithelial cells
    • SGLT 1
    • Glut 5
    • Glut 2
  7. SGLT 1
    • Luminal membrane of GI epithelial cells
    • Co-transport Na and glucose or galactose into epithelial cell
  8. Glut 5
    • Luminal membrane of GI epithelial cells
    • Transports fructose into epithelial cells
  9. Glut 2
    • Basal membrane of GI epithelial cells
    • Transports monosaccharides out of GI epithelial cells into interstitial space
  10. Glucose enters liver by facilitated transport through ________
    Glut 2 transporters
  11. Increase in plasma blood glucose --> Pathway in liver
    • Increased glucose
    • Enters hepatocytes through GLUT2 transporters
    • Glucose ---(glucokinase)---> G6P
    • 2 fates of G6P: G6P ---> glycogen synthesis (enhanced by insulin); G6P ---> triglyceride storage
  12. Increase in plasma blood glucose --> Pathway and effects in beta cells of pancreas
    • Glucose enters beta cells through GLUT2
    • Glycolysis + krebs cycle, etc.
    • Increased ATP
    • ATP sensitive K channels close --> membrane depolarization
    • V-gated Ca channels open
    • Influx of calcium into the cell; calcium induced calcium release
    • Fusion of insulin containing secretory vesicles to membrane
    • Insulin released
  13. Most potent stimulator of insulin secretion?
  14. Insulin (stimulates/inhibits) hepatic gluconeogenesis and glycogenolysis and (stimulates/inhibits) glycogenesis
    • Inhibits
    • Stimulates
  15. Insulin (stimulates/inhibits) glycogen synthesis by (activating/deactivating) glucokinase and glycogen synthase
    • Stimulates
    • Activating
  16. Insulin (stimulates/inhibits) glycogen phosphorylase activity
  17. Insulin (stimulates/inhibits) G-6-phosphatase
  18. Insulin (stimulates/inhibits) glucose uptake into skeletal muscle cells and adipocytes
  19. Insulin stimulates glucose uptake into skeletal muscle cells and adipocytes via _______ transporters
  20. GLUT4 Translocation Pathway in skeletal muscle cells and adipocytes
    • Insulin binds to its protein kinase receptor
    • Recruits and phosphorylates IRS
    • IRS stimulates PI3K
    • PI3K converts PIP2 to PIP3
    • PIP3, with PDK, activates Akt (protein kinase B)
    • Akt phosphorylates AS160
    • This inhibits AS160, allowing GLUT4 to move to the membrane and bring glucose into the cell
  21. Muscle contraction (exercise) (stimulates/inhibits) GLUT4 translocation into muscle membrane
  22. Mechanism by which exercise stimulates glucose uptake
    • Exercise stimulates AMPK (AMP activated kinase)
    • AMPK stimulates phosphorylation of AS160
    • Promotes GLUT4 translocation
  23. Fat digestion and absorption occurs almost entirely in _________
    the small intestine
  24. Chylomicrons
    Lipoproteins that transport dietary triglycerides and cholesterol from small intestine to body's cells
  25. _______ breaks down chylomicrons
    lipoprotein lipase (LPL)
  26. VLDL
    Transport triglycerides and cholesterol from liver to body's cells
  27. VLDL degraded into ______, which is degraded into ________
    • IDL
    • LDL
  28. LDL
    lipoproteins that carry cholesterol to the body's cells
  29. HDL
    lipoproteins that carry cholesterol back from tissues and organs to the liver where it will be degraded or recycled
  30. Major hormones of post absorptive state
    • Glucagon
    • Cortisol
    • Epinephrine
    • NE
    • GH
  31. Goal of post absorptive state
    Increase blood glucose and spare it for the brain