Gi function

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Gi function

  1. 1. OVERVIEW OF GASTROINTESTINAL FUNCTION & REGULATION 簡介 胃腸功能及其調節     黃士哲 (Shih-Che Huang) <ul><li>OBJECTIVES 教學目標
  2. 2. Understand gastrointestinal function </li></ul><ul><ul><li>structure of the gastrointestinal tract 胃腸構造
  3. 3. major gastrointestinal secretions 胃腸分泌
  4. 4. major hormones, peptides, and neurotransmitters 荷爾蒙 生肽 神經傳導物質
  5. 5. enteric nervous system and splanchnic circulation 腸神經系統 內臟循環 </li></ul></ul>
  6. 6. 胃腸構造 Organization of the wall of the intestine into functional layers
  7. 7. 腸構造 structure of intestinal villi 絨毛 and crypts 窩
  8. 8. Regulation of salivary secretion 唾液分泌 parasympathetic nervous system 副交感神經 ACh, acetylcholine.
  9. 9. Anatomy of the stomach 胃
  10. 10. Structure of a gastric gland 胃腺 from the fundus 底部 and body 體部 of the stomach
  11. 11. ECL (enterochromaffin-like) cells 腸親色素細胞 <ul><li>More than 15 types of hormone-secreting enteroendocrine cells 腸內分泌細胞 </li></ul><ul><ul><li>in the mucosa of the stomach, small intestine, and colon.
  12. 12. G cells, S cells, etc. </li></ul></ul><ul><li>Others manufacture serotonin or histamine and are called enterochromaffin or enterochromaffin-like (ECL) cells </li></ul>
  13. 13. Contents of Normal Gastric Juice 胃液 (Fasting State 禁食 ) <ul><li>Cations: Na+, K+, Mg2+, H+ (pH 1.0)
  14. 14. Anions: Cl–, HPO4 2–, SO4 2–
  15. 15. Pepsins 胃蛋白酶
  16. 16. Lipase 脂肪酶
  17. 17. Mucus 黏液
  18. 18. Intrinsic factor 內因子 </li></ul>
  19. 19. Intrinsic factor 內因子 absorption 吸收 of vitamin B12
  20. 20. Regulation of gastric acid 胃酸 and pepsin 胃蛋白酶 secretion (SST somatostatin 體抑制素 )
  21. 21. Parietal cell 壁細胞 receptors 受體
  22. 22. Ion transport 離子運輸 proteins of parietal cells 壁細胞
  23. 23. Clinical Box –1 Peptic Ulcer Disease 消化性潰瘍 <ul><li>Breakdown of mucosa barrier </li></ul><ul><li>Infection with the bacterium Helicobacter pylori 幽門螺旋桿菌 disrupts this barrier
  24. 24. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) 消炎止痛藥 </li></ul><ul><ul><li>inhibit the production of prostaglandins
  25. 25. decrease mucus and HCO3 – secretion </li></ul></ul>
  26. 26. Clinical Box –1 Peptic Ulcer Disease 消化性潰瘍 <ul><li>Inhibition of acid secretion 抑制 酸分泌 </li></ul><ul><ul><li>cimetidine </li><ul><li>block the H2 histamine 組織氨 receptors 受體 </li></ul><li>omeprazole (proton pump inhibitor 質子幫浦抑制劑 ) </li><ul><li>inhibit H+–K+ ATPase on parietal cells </li></ul></ul></ul><ul><li>H. pylori 幽門螺旋桿菌 can be eradicated with antibiotics 抗生素
  27. 27. NSAID 消炎止痛藥 -induced ulcers </li></ul><ul><ul><li>stopping the NSAID </li></ul></ul>
  28. 28. PANCREATIC SECRETION 胰臟分泌
  29. 29. Principal Digestive Enzymes 酵素 ( 酶 ) <ul><li>Stomach 胃
  30. 30. Pepsins 胃蛋白酶 Proteins  Polypeptides 多生肽 </li></ul><ul><li>Pancreas 胰臟
  31. 31. Trypsin 胰蛋白酶 Proteins  Polypeptides
  32. 32. Lipase 脂肪酶 Triglycerides  Monoglycerides, fatty acids
  33. 33. Amylase 澱粉酶 Starch  Dextrins, maltotriose, maltose </li></ul>
  34. 34. Liver, gallbladder 膽 , and pancreas 胰
  35. 35. Human bile acids 膽汁酸
  36. 36. Lipid digestion 脂質消化 and passage to intestinal mucosa 腸黏膜
  37. 37. circulation of bile acids 膽汁酸循環
  38. 38. Daily Water Turnover (mL) in the Gastrointestinal Tract <ul><li>Ingested 入 2000
  39. 39. Endogenous secretions 分泌 7000 </li></ul><ul><ul><li>Salivary glands 1500
  40. 40. Stomach 2500
  41. 41. Pancreas 1500 </li></ul></ul><ul><li>Total input 9000
  42. 42. Reabsorbed 回收 8800 </li></ul><ul><ul><li>Jejunum 5500, Ileum 2000, Colon 1300 </li></ul></ul><ul><li>Balance in stool 200 </li></ul>
  43. 43. NaCl absorption in the small intestine and colon
  44. 44. Sodium 鈉離子 absorption in the colon
  45. 45. Chloride 氯離子 secretion 分泌 in the small intestine and colon
  46. 46. Lubiprostone ( 便秘 新藥 ) <ul><li>Lubiprostone is an oral fatty acid that activates chloride channels on the intestinal epithelial cells, secreting chloride and water in the gut lumen </li></ul><ul><ul><li>improve constipation 便秘 </li></ul></ul>
  47. 47. Clinical Box–2 A 40 y/o male patient with Epigastric pain 上腹痛 for 1 day <ul><li>Chronic alcohol intake
  48. 48. Pain was severe; moving would aggravate 加重 ; bending forward relieved pain
  49. 49. Vomiting </li></ul>
  50. 50. Clinical Box–2 Acute pancreatitis ( 急性胰臟炎 ) <ul><li>Lipase 6597 IU/L (normal < 100 IU/L)
  51. 51. Amylase 1627 IU/L (normal < 200 IU/L)
  52. 52. Admission diagnosis 住院診斷 : ACUTE PANCREATITIS </li></ul>
  53. 53. Clinical Box–2 Acute pancreatitis ( 急性胰臟炎 ) <ul><li>premature activation of zymogens ( 酵素早期活化 )
  54. 54. ASSOCIATED FACTORS ( 常見 相關因素 ) </li></ul><ul><ul><li>Gallstones ( 膽結石 )
  55. 55. Alcohol ( 酒 ) </li></ul></ul>
  56. 56. Polypeptides 多生肽 in Gastrointestinal Tract <ul><li>Gastrin 胃泌素 (produced by G cells in antrum) </li></ul><ul><ul><li>acid secretion </li></ul></ul><ul><li>Cholecystokinin 膽囊收縮素 (cells in the mucosa of the upper small intestine) </li></ul><ul><ul><li>stimulation of pancreatic enzyme secretion </li></ul></ul><ul><li>Secretin 分泌素 (S cells in the glands of the mucosa of the upper small intestine) </li></ul><ul><ul><li>bicarbonate by the duct cells of the pancreas and biliary tract </li></ul></ul>
  57. 57. Sites of production of the five gastrointestinal hormones along the length of the gastrointestinal tract
  58. 58. GLP-1 (glucagon 昇糖素 -like peptide 1) ( 糖尿病新藥 )
  59. 59. MOTILIN 運動素 - Migrating motor complexes (MMCs) 移動 式複合 運動
  60. 60. ENTERIC NERVOUS SYSTEM 腸神經 <ul><li>myenteric plexus ( 腸神經叢 ) </li></ul><ul><ul><li>between the outer longitudinal 縱走肌 </li></ul></ul>and middle circular muscle 環狀肌 layers <ul><li>submucous plexus ( 黏膜下神經叢 ) </li></ul><ul><ul><li>between the middle circular layer 環狀肌 </li></ul></ul>and the mucosa 黏膜
  61. 61. ENTERIC NERVOUS SYSTEM 腸神經系統 <ul><li>myenteric plexus 腸神經叢 </li></ul><ul><ul><li>motor 運動 control </li></ul></ul><ul><li>submucous plexus 黏膜下神經叢 </li></ul><ul><ul><li>glandular epithelium, intestinal endocrine cells, and submucosal blood vessels
  62. 62. intestinal secretion 分泌 </li></ul></ul>
  63. 63. ENTERIC NERVOUS SYSTEM 腸神經系統 <ul><li>Neurotransmitters 神經傳導物質
  64. 64. acetylcholine, norepinephrine, serotonin,  -aminobutyrate (GABA), the gases NO and CO, peptides
  65. 65. Some of these peptides also act in a paracrine 旁分泌 fashion or enter the bloodstream 血流 , becoming hormones
  66. 66. most of them are also found in the brain 腦 </li></ul>
  67. 67. EXTRINSIC INNERVATION <ul><li>Parasympathetic 副交感神經 cholinergic activity </li></ul><ul><ul><li>increasing the activity of intestinal smooth muscle </li></ul></ul><ul><li>Sympathetic 交感神經 noradrenergic activity </li></ul><ul><ul><li>decreasing the activity of intestinal smooth muscle
  68. 68. causing sphincters to contract </li></ul></ul>
  69. 69. GASTROINTESTINAL (SPLANCHNIC) CIRCULATION 內臟循環
  70. 70. SUMMARY <ul><li>Gastrointestinal functions are regulated in an integrated fashion by endocrine, paracrine, and neurocrine mechanisms.
  71. 71. Hormones and paracrine factors are released from enteroendocrine cells in response to signals coincident with the intake of meals. </li></ul>
  72. 72. SUMMARY Brain gut axis <ul><li>The enteric nervous system conveys information from the central nervous system to the gastrointestinal tract, but also often can activate programmed responses of secretion and motility in an autonomous fashion. </li></ul>
  73. 73. SUMMARY Portal system <ul><li>The intestine has an unusual circulation.
  74. 74. The majority of its venous outflow does not return directly to the heart, but rather is directed initially to the liver via the portal vein. </li></ul>
  75. 75. Reference <ul><li>Ganong’s Review of Medical Physiology </li></ul><ul><ul><li>McGraw Hill; 23rd ed, 2010
  76. 76. KE Barrett, SM Barman, S Boitano, HL Brooks </li></ul></ul><ul><li>Harrison's Principles of Internal Medicine </li></ul><ul><ul><li>McGraw-Hill; 17 edition, 2008
  77. 77. Fauci AS, Braunwald E, Kasper DL </li></ul></ul><ul><li>Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management </li></ul><ul><ul><li>M Feldman, LS Friedman, LJ Brandt
  78. 78. Saunders; 9th ed, 2010 </li></ul></ul>

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