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2015-09-07 18:02:37
vetmed endocrinology pancreas

vetmed endocrinology pancreas
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  1. Exocrine and endocrine pancreas are derived from the __________.
    multi-potent alimentary entoderm (from endoderm)
  2. The pancreas is part of the _________ system.
  3. Most of the pancreatic tissue is __________.
    exocrine pancreas
  4. Portion of the pancreas that produces bicarbonate, proteases, lipases, and amylase and delivers it to the small intestine.
    exocrine pancreas
  5. Portion of the pancreas that is composed of islets that secrete insulin, glucagon, and other hormones.
    endocrine pancreas
  6. Islet that produces glucagon.
    alpha cells
  7. Islet that produces insulin and amylin.
    beta cells
  8. Islet that produces somatostatin.
    delta cells
  9. Venous blood from the pancreas, containing high concs of pancreatic hormones, drains into the _________ from the __________; the __________ within the pancreas ensures the distribution of pancreatic hormones within the pancreas itself.
    liver; portal venous system; portal venous system
  10. Describe the configuration of cells within an islet of langerhans.
    beta cells are in the center and alpha cells are around the periphery
  11. What is unique about equine islets?
    beta cells are around the periphery instead of the center (opposite)
  12. Function of pancreatic somatostatin.
    paracrine inhibition of other islet hormones
  13. Processing of pro-insulin occurs in the _________; therefore, it is already packed and C-peptide (inert by-prouduct) is released in a __________.
    golgi apparatus; 1:1 ratio with insulin
  14. The processing of pro-insulin within the vesicle is __________; therefore, you always have a small amount of _________ released with __________.
    never complete; pro-insulin; insulin and C peptide
  15. What is unique about the AA sequence of insulin in felines?
    has His (charged) where other species have a neutral AA--> no known clinical significance
  16. Transcription of insulin is primarily controlled by __________, which controls insulin production over ________ and controls the ________ of insulin _____.
    glucose; hours; half-life; mRNA
  17. _______ transporters are independent of insulin for facilitated diffusion of glucose into the cell.
  18. _________ is the glucose sensor of the beta cell; as glucose increase, so does its function, which is...
    glucokinase; phosphorylating glucose to G6P
  19. Describe what it means when you say that glucokinase exhibits sigmoid kinetics.
    it is most sensitive to changes in blood glucose conc within the physiological range
  20. Glucose enters the beta cell though _______; it is then trapped inside the cell by ________.
    GLUT2; glucokinase (phosphorylates it)
  21. G6P enters _______ and subsequently increases intracellular ______; this increase leads to the ____________ and ultimately _________.
    glycolysis; ATP; closure of ATP-sensitive K+ channels; depolarization of the membrane
  22. Depolarization of the beta-cell membrane has the immediate effect of ________________, which leads to...
    opening voltage-gated Ca2+ channels and allowing Ca2+ to enter the cell; release of secretory granules
  23. Depolarization of the beta-cell membrane has the delayed effect of ______________, which leads to...
    opening voltage-gated K+ channels and allowing K+ to leak back into the cell; repolarization and termination of secretory signal.
  24. Closure of ATP-sensitive potassium channels can be promoted by drugs from the _____________ family.
  25. Fusion of insulin secretory granules with the membrane requires... (2)
    calcium and energy
  26. Acute regulation of insulin production is mainly controlled at the level of ________ by the effect of ________ of ___________.
    protein translation;glucose; increasing the half-life of insulin mRNA
  27. _________ stimulates all stages of biosynthesis and secretion of insulin.
  28. Describe the process of regulation of insulin secretion from the beta cell.
    glucose uptake by GLUT2--> glu phosphorylated to G6P by glucokinase--> glycolysis--> ATP is produced--> ATP sensitive K+ channels open--> K+ depolarizes voltage-gated Ca2+ channel--> Ca2+ enters cells and participates in the release of primed insulin vesicles
  29. Diazoxide is used to treat _______ because it inhibits closure of the K+ channel, preventing depolarization, thus....
    insulinoma; preventing insulin from being released
  30. When you bathe beta cells in glucose, describe the series of events that lead to cell memory.
    spike in insulin release from previously primed vesicles--> rapid decline in insulin--> gradual increase in insulin as more vesicles are primed--> next glucose exposure more vesicles will be primed initially so larger initial spike
  31. Increasing blood glucose stimulates the immediate __________ and also stimulates the...
    secretion of insulin from secretory pool; move of granules from the reserve pool to the secretory pool
  32. What is priming?
    one stimulation increases the response of the beta cell to future stimulation
  33. Although the main control of insulin release is glucose, it can be modified by...
    inhibitors (galanin, somatostatin, alpha2 adrenergic agonists) and potentiators (glucagon, GIP, GLP-1, beta adrenergic agonists)
  34. The half-life of insulin is _______; insulin is degraded in ________.
    short; target organs, mainly liver (also muscle, kidney, fat)
  35. The __________ system acts to potentiate insulin secretion, while the _________ system can potentiate or inhibit secretion (usually inhibit).
    parasympathetic; sympathetic
  36. The insulin receptor is an _______; insulin binds with high affinity to the alpha subunit and actives the ________ of the beta subunit, leading to...
    RTK; tyrosine kinase; internalization of the receptor and insulin molecule (receptor is subsequently recycled)
  37. Biological actions of insulin on the whole body. (6)
    lowers blood glucose conc [increase glycolysis, increase synthesis of glycogen, decrease glycogen lysis] increase synthesis of fat and protein, decrease breakdown of fat and protein
  38. Insulin is a(n) ________ hormone.
  39. Insulin does not affect glucose ___________; it diffuses down the _______ by way of _______.
    entering hepatocytes; conc gradient; GLUT2
  40. Biological actions of insulin in the liver. (5)
    increase glycolysis, increase glycogen, decrease gluneogenesis, increased synthesis of FFA, increase protein synthesis
  41. After a glucose-rich meal,  ________ is secreted and glucose in the liver is used as ___________, while the remainder is stored as _________ or ________.
    insulin; an energy source; glycogen; in fatty acids
  42. GLUT2 is expressed in what organs?
    pancreatic beta-cell, liver, and brain
  43. Because GLUT2 is insulin-independent, glucose conc within beta cells and hepatocytes _________ in comparison to that of extracellular fluid.
    is similar (glucose conc is much lower in other body cells that don't have GLUT2)
  44. Biological actions of insulin in muscle. (4)
    increase glucose uptake, increase glycolysis, increase glycogen, increase protein synthesis
  45. Insulin promotes the uptake of glucose into muscles cells by facilitating...
    translocation of GLUT4 to the plasma membrane.
  46. What is the only instance in which glucose does not act as an anabolic steroid?
    insulin decreases glucose production and release from the liver
  47. Biological affect of insulin on adipose tissue. (3).
    increases fat synthesis, promote glucose uptake into adipocytes (translocated GLUT4 to plasma membrane), prevents lipolysis
  48. ________ has a low affinity to the insulin receptor; therefore, it lingers longer in circulation. In _________, it is in higher concs into the blood than normal and can be interpreted as insulin resistance.
    Pro-insulin; diabetes
  49. Why is C-peptide a useful marker of insulin secretion?
    it is secreted in equi-molar concentrations to insulin (1:1), excreted by the kidneys with simple kinetics
  50. What are the biological actions of insulin and amylin acting in concert? (3)
    slow gastric emptying, promote satiety, inhibit secretion of glucagon during hyperglycemia
  51. Glucagon receptors are expressed in what organs?
    liver and kidneys
  52. What are the actions of glucagon. (3)
    prevents hypoglycemia, increase blood glucose (insulin antagonist), opposes action of insulin in the liver
  53. The primary site of action of glucagon is in the ________.
  54. __________ determines [cAMP] in hepatocytes.
    Insulin:glucagon ratio
  55. Glucagon is stimulated by... (4)
    low serum glucose, catecholamines, AAs, sympathetic nerve stimulation
  56. Glucagon secretion is suppressed by... (3)
    insulin, amylin, GLP-1
  57. Increased glucagon inhibits _________, decreases __(2)__, and allows _______ to enter the ________.
    glycolysis; glycerol and TG output; FA; mitochondria
  58. ________ inhibits cAMP; ________ stimulates cAMP.
    Insulin; glucagon
  59. What are the effects of increases in hepatocellular intracellular cAMP? (7)
    increased glycogen lysis, release of glucose to blood, inhibits glycogen synthase, activate gene transcription for gluconeogenesis, decreases FFA synthesis, decreases glucagon secretion, increased ketone production
  60. What is the ultimate goal of glucose homeostasis?
    to meet the constant and unchanging energy demand of the brain
  61. What are the sources of energy that the brain can utilize?
    glucose and ketones (NOT FFA)
  62. In the fasting state, the liver releases ___________ under the influence of relatively high ________ conc and relatively low _______ conc.
    glucose; glucagon; insulin
  63. During increased physical activity, increased __________ in muscles is met by increasing __________; to allow this, the _________ needs to increase.
    energy demand; hepatic glucose output; glucagon/insulin ratio
  64. In most tissues, glucose is trapped inside cells by _________; in the liver, release of glucose back into circulation is facilitated by expression of __________.
    phosphorylation to G6P;glucose-6-phosphatase (G6P--> glucose)
  65. Without the presence of insulin, uptake of ________ into ________ diminishes.
    glucose; fat and muscles
  66. Glucose uptake into the brain is determined by ________ and ________ because brain cells express ________.
    demand; blood glucose conc; GLUT1 (insulin-independent)
  67. Immediate steps in prevention of hypoglycemia. (2)
    decrease insulin, increase glucagon
  68. Intermediate steps of prevention of hypoglycemia. (1)
    increase catecholamines
  69. Long-term steps to prevention of hypoglycemia. (3)
    increase cortisol, increase GH, increase ghrelin
  70. In the fasted state, the main organs responsible for maintaining fuel homeostasis are... (5)
    liver and kidney (glucose production), brain (dependence on glucose), muscle and adipose (ability to store energy)
  71. Catecholamines increase ________ and ________ use in ________.
    glucose; glycogen lysis; muscles
  72. What is responsible for hyperglycemia associated with acute stress (as in cats)?
  73. GH increases ________ in muscle and fat by decreasing _________, increasing ________, increase the synthesis and decreasing the breakdown of _________, and increasing the breakdown of ________.
    insulin resistance; glucose uptake; hepatic glucose output; proteins; fat
  74. Stimulation for GH secretion. (5)
    hypoglycemia, fasting, exercise, ghrelin, GHRH
  75. Cortisol increases __________ in muscles and adipose, thus shunting more glucose to the _________; it also stimulates _________ in muscles.
    insulin resistance; brain; proteolysis
  76. Glucose enters the GI tract and is sensed by specialized enteroendocrine cells, sending a signal to the pancreas that is translated into increased __________ and enhanced ___________.
    glucose sensitivity; glucose-dependent insulin secretion
  77. For any given increase in blood glucose conc that is the result of entry through the GI tract, more insulin and less glucagon are secreted than when compared to the same increase in blood glucose conc by other routes of entry (ie. IV).
    incretin effect
  78. What are the 2 incretin hormones?
    GLP-1 and GIP
  79. GIP and GLP-1 increase _________, which has the following effects on pancreatic beta cells... (4)
    cAMP; increased glucose sensitivity, increase in glucose-dependent insulin secretion, increased insulin biosynthesis, inhibition of apoptosis and stimulation of proliferation of beta cells
  80. Outside of beta cells, GIP stimulates... (2)
    glucagon secretion, insulin sensitivity in adipose tissue.
  81. Outside of beta cells, GIP decreases... (1)
    gastric acid secretion.
  82. Outside of beta cells, GLP-1 increases...(1)
  83. Outside of beta cells, GLP-1 decreases...(4)
    glucagon secretion, rate of gastric emptying, gastric acid secretion, proximal GI motility and secretion
  84. GIP secreting endocrine cells.
    K cells
  85. GLP-1 secreting cells.
    L cells
  86. GIP and GLP-1 are inactivated by _______ and secreted in the ________.
    DPP-4; kidneys
  87. Most synthesis of fatty acids occurs in the _______.
  88. Functions of adipose tissue. (3)
    energy storage, insulation, hormonal regulation
  89. Circulating adiponectin levels are negatively correlated with _________.
    body mass index
  90. The decrease in adiponectin with obesity is more severe with _________ than _________ adiposity.
    visceral; subcutaneous
  91. How does insulin affect adiponectin?
    increases secretion of adiponectin, decreases expression of adiponectin receptors
  92. Adiponectin _______ insulin sensitivity and ________ beta-oxidation in the liver and muscles.
    increases; increases
  93. Overall, the effects of adiponectin on liver and muscle contribute to increased __________, lower _________, and decreased ___________.
    insulin sensitivity; blood glucose; tissue TG content
  94. _________ is constitutively secreted by adipocytes, and its regulation depends upon energy flux within adipocytes.
  95. Serum concs of leptin are predominantly determined by _________.
    body fat mass
  96. Increased body fat mass leads to _________ circulating leptin concentrations.
  97. Leptin inhibits _________.
    insulin secretion
  98. What effect does insulin have on leptin concentration?
    increased insulin--> increased fat mass--> increase leptin conc
  99. What enables ghrelin to penetrate through the BBB?
    acyl group
  100. Ghrelin is a potent _________ and is the only known circulating ____________.
    GH secretion promoter; orexigenic peptide
  101. What are the effects of ghrelin? (4)
    increases appetite, increases body weight, stimulates gastric secretion and motility, decreases fat mobilization
  102. Secretion of ghrelin is inhibited by _________.
    fat in stomach
  103. ____________ is a negative incretin or decretin, a negative potentiator of _________ secretion.
    Acylated- ghrelin; insulin
  104. __________ ghrelin is a potential stimulator of insulin secretion.
  105. Leptin stimulates __________ neurons in the ________ center of the hypothalamus; it suppresses _________ neurons in the hypothalamus.
    anorexigenic/catabolic; satiety; orexigenic/anabolic
  106. What are the effects of leptin? (4)
    apetite suppression, decreased fat mass and body weight, increased energy expenditure, increased thermogenesis (via sympathetic nn)