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Flashcards

GIT Physiology

Adrianna Bialecka Physiology Organs University English 97 cards

Overview of GIT

Cards in this deck (97)

  1. 1Overview of GITOverview of GIT
  2. 2What are the 4 main layers of the tubular part of the GIT?1. Mucosa
    2.Submucosa
    3.Muscularis/Muscularis externa/Muscularis propria
    4. Adventitia (outside of peritoneum)/Serosa (inside peritoneum)    What are the 4 main layers of the tubular part of the GIT?
  3. 3What locally controls the GIT?What locally controls the GIT?
  4. 4What is the enteric nervous system connected to?ANSWhat is the enteric nervous system connected to?
  5. 5What are the two components of neural control of GIT?-Local control (enteric nervous system)
    -External influence (autonomic nervous system)
  6. 6What controls parasympathetic activity?-Vagus (medulla)
    -Pelvic nerve (sacral roots)
    -Generally excitatory (Ach) . Increases motility and secretion    What controls parasympathetic activity?
  7. 7What controls Sympathetic activity?-Sympathetic ganglia
    -Generally inhibitory (NA): Decreases motility and secretion    What controls Sympathetic activity?
  8. 8What controls sphincter muscles?-Basal tone from sympathetic fibres
    -Parasympathetic inputs are relaxant (nitric oxide, vasoactive intestinal peptides, not ACh)
  9. 9What are the first steps of digestion?-Mastication
    -Bolus preparation
    -Enzymatic digestion
    -Food content sensing
    -Delivery of appropriately sized bolus to the stomach
  10. 10What are the three main pairs of salivary glands?-Parotid
    -Submandibular
    -Sublingual
    >Plus many minor mucosal glands throughout the mouth    What are the three main pairs of salivary glands?
  11. 11What is the composition and function of saliva?What is the composition and function of saliva?
  12. 12What controls salivary production?-Neural not hormonal control
    -Stimulated by taste, smell and even thought of food
    -Parasympathetic (increased volume secretion) and sympathetic (thickening) innervation
  13. 13What are the sequence of events during swallowing?-Soft palate elevated
    -Larynx elevated and vocal cords adducted
    -Apnoea (temporary cessation of breathing)
    -Upper esophageal sphincter open (0.5s)
    -Pharyngeal muscles contract behind bolus
    -Upper esophageal sphincter closes
    -Lower esophageal sphincter open (5s)
    -Esophageal peristalsis away from the direction of the mouth
    -Fundus of stomach (dome-shaped superior portion of stomach) relaxes receptively
    -Lower esophageal sphincter closed    What are the sequence of events during swallowing?
  14. 14What is Peristalsis?-Wave-like contraction promoting motility in the GIT
    -Involves inner circular muscle and outer longitudinal muscle (the 2 layers of the muscularis externa)
    -Squeezes material down the GIT away from the mouth
    -Contraction behind the bolus
    -Relaxation ahead of the bolus
  15. 15Structure of the OesophagusStructure of the Oesophagus
  16. 16Oesophagus histologyOesophagus histology
  17. 17Gastro-oesophageal junction histologyGastro-oesophageal junction histology
  18. 18What is the use of Barium Sulphate in radiography of the GIT?-Thick liquid
    -Used as a contrast agent to visualise the intestinal tract (blocks X-ray beams)
    -Swallowed by patientss (or given as an enema)
    -Coats the mucosa of the intestinal tract
    -Used to examine physiological processes e.g. swallowing, gastric emptying, colonic motility (when given as an enema)
  19. 19What does normal barium swallowing look like?What does normal barium swallowing look like?
  20. 20What does Oesophageal Achalasia look like?What does Oesophageal Achalasia look like?
  21. 21What does a corkscrew Oesophagus look like?What does a corkscrew Oesophagus look like?
  22. 22What is the structure of the stomach?What is the structure of the stomach?
  23. 23What are the functions of the stomach?Storage- increase in stomach volume
    Mixing- Gastric motility
    Digestion- Gastric motility and gastric acid production
  24. 24How does the structure of the stomach reflect its function?How does the structure of the stomach reflect its function?
  25. 25Fundus histologyFundus histology
  26. 26Pylorus HistologyPylorus Histology
  27. 27What are the key stomach cell types?Surface mucous cell
    -Thick mucous, high in bicarbonate
    Mucous neck cell
    -Present in neck or isthmus
    -less columnar-rounded nuclei
    -less alkaline secretion -containing mucin
    Parietal cell
    -Present in neck and deeper parts of gland
    -Strong eosinophilic staining
    -Intracellular canaliculus -ultrastructure
    -Secretes HCl and intrinsic factor
  28. 28What are the key stomach cell types- part 2?Chief cell
    -lower regions (base) of the gastric gland
    -Produces pepsinogens and gastric lipase
    Enteroendocrine cells
    -Gastrin producing cells (G-cells) in pylorus
  29. 29What is gastric content?-Hydrochloric acid (HCl) pH 1-2
    -Pepsinogens ->Pepsins ->broad spectrum proteases
    -Gastric lipase
    -Mucous: Bicarbonate rich, pH at epithelial surface around 7
    -Intrinsice factor
  30. 30What is the main substrate digested by the stomach?protein
  31. 31What controls GIT processes?What controls GIT processes?
  32. 32What are some GI relfex triggers?-Distension by luminal contents
    -Osmolarity of chyme
    -Acidity of chyme
    -Digestion products e.g. fatty acids, peptides, amino acids
  33. 33What are long neural reflex pathways and short neural reflex pathways?What are long neural reflex pathways and short neural reflex pathways?
  34. 34Examples of Gastrointestinal hormones and their site of production?Examples of Gastrointestinal hormones and their site of production?
  35. 35How is Gastric Acid secretion regulated/controlled?How is Gastric Acid secretion regulated/controlled?
  36. 36Visual representation showing gastric acid secretion in stomach?Visual representation showing gastric acid secretion in stomach?
  37. 37Diagram showing regulation/control of gastric acid secretion at parietal cellDiagram showing regulation/control of gastric acid secretion at parietal cell
  38. 38Pathways of gastric acid secretion regulationPathways of gastric acid secretion regulation
  39. 39Mini-summary of Gastric acid secretion regulation-Gastric acid secretion is a highly controlled process
    -Cephalic, gastric and intestinal phases
    -Multiple inputs- Autonomic, enteric and hormonal
    -Feed back regulatory control
  40. 40What is the function of the small intestines?-Completion of Digestion
    -Majority of Absorption
    -Secretion
  41. 41What are the 3 distinct regions of the small intestine?-Duodenum (nearest the stomach, proximal SI, receives pancreatic and biliary secretions
    -Jejunum (middle section of SI, post-duodenum, major site of absorption)
    -Ileum (nearest the colon, distal SI, joins to the large intestine)
  42. 42What are the surface area adaptations of the small intestine?-Plicae
    -Villi
    -Microvilli    What are the surface area adaptations of the small intestine?
  43. 43What is the structure of the pancreas and the duodenum?What is the structure of the pancreas and the duodenum?
  44. 44What are the two functional portions of the pancreas?-Endocrine: Islets of Langerhans produces the hormones insulin and glucagon (minority)
    -Exocrine: Pancreatic acini and ducts produce the pancreatic juices
  45. 45Histology showing exocrine and endocrine cellsHistology showing exocrine and endocrine cells
  46. 46What are the two components of the pancreatic juice?-The pancreas weighs approx 100g, but produce 1 litre of pancreatic juice/day
    2 components:
    >Aqueous component
    >Enzymatic component
  47. 47What parts secrete which component?What parts secrete which component?
  48. 48What are the different pancreatic enzymes secrete and the substrate they work on?What are the different pancreatic enzymes secrete and the substrate they work on?
  49. 49How does the proteolytic enzymes act in a cascade?They activate the inactive formsHow does the proteolytic enzymes act in a cascade?
  50. 50How does the duodenum act as a reaction vessel?-Bile produced in liver, stored in gallbladder
    -Acid neutralised by Pancreas -bicarbonate
    -Enzymes produced by pancreas
  51. 51Histology diagram of jejunumHistology diagram of jejunum
  52. 52Histology diagram showing intestinal vasculatureHistology diagram showing intestinal vasculature
  53. 53What is the anatomy of the large intestine?What is the anatomy of the large intestine?
  54. 54What does the histology diagram look like for the large intestine?What does the histology diagram look like for the large intestine?
  55. 55Diagram showing the structure of the large intestinesDiagram showing the structure of the large intestines
  56. 56What does the muscularis externa look like in the histology of large intestines?What does the muscularis externa look like in the histology of large intestines?
  57. 57What are the labels of the histological diagram of the colon?What are the labels of the histological diagram of the colon?
  58. 58What are the functions of the colon?-Retain contents for a long period
    -Storage
    -Mix contents over a long period
    -Facilitate reabsorption of water/electrolytes (Na+/Cl-)
    -Move to allow voluntary extrusion of faeces
    -Immunological- Gut associated lymphoid tissue
  59. 59What are the functions of the different parts of the large intenstine?What are the functions of the different parts of the large intenstine?
  60. 60How does the large intestine mixing work?Haustral shuttling
    -Most common
    -Short distances- both directions
    -squirting of contents -kneading the fecal mass
  61. 61How does the large intestine moving work?Peristalsis
    -haustram to haustrum
    Mass movements/Mass contraction/ Multihaustral propulsion
    -infrequent -several hour interval
    -produced reflexively by gastrocolic reflax-after meals
    -Moves fecal mass over large distances
  62. 62What does propulsive motility in the colon?What does propulsive motility in the colon?
  63. 63What are the 4 aspects to the control of colonic motility?-Basal electrical rhythm
    -Intrinsic nerves -ENS
    -Extrinsic nerves -ANS
    -Endocrine/paracrine control
  64. 64What are the 7 types of stool consistencies?What are the 7 types of stool consistencies?
  65. 65What is the residue combustor desiccator and pelleter?What is the residue combustor desiccator and pelleter?
  66. 66What are some colon motility problems?Constipation
    -Fecal transit through the colon is too lsow
    Diarrhoea
    -Fecal transit through the colon is too fast
  67. 67What is an examples of a colon motility disorder?Megacolon
    -Impaired contractile function of the colon    What is an examples of a colon motility disorder?
  68. 68What is the structure of the liver?What is the structure of the liver?
  69. 69What is the structure of the liver?What is the structure of the liver?
  70. 70What doe the Hepatic portal vein do?What doe the Hepatic portal vein do?
  71. 71What is the portal system?What is the portal system?
  72. 72What are the different components that make up the liver structure?What are the different components that make up the liver structure?
  73. 73What is the histology diagram of the liver?What is the histology diagram of the liver?
  74. 74How is the liver structurally organised?How is the liver structurally organised?
  75. 75Where is bile produced?produced in the liver stored in the gall bladder
    -Approx 600-1000 mls produced per day
  76. 76What are the functions of bile?1. Emulsification of lipids
    2. Hormonal action
    3. Elimination of waste products e.g. bilirubin
  77. 77What is the composition of bile?Water, bile salts, electrolytes e.g. HCO3-, lecithin, cholesterol, bilirubin, vitamins, proteins
    -Bile salts synthesised by the hepatocytes
    -Aqueous components contributed by bile duct epithelial cells
    -Secretin stimulates duct cell but not affect bile salt synthesis
  78. 78What are some examples of Bile Salts/Bile acids?What are some examples of Bile Salts/Bile acids?
  79. 79How are lipids emulsified by bile?How are lipids emulsified by bile?
  80. 80What are the key steps in Digestion?What are the key steps in Digestion?
  81. 81What does the oral cavity digestion?-Some carbohydrate =role of salivary amylase
  82. 82What does the stomach digestion?-Mainly protein = Role of HCl, pepsin and motility
  83. 83What does the small intestine digestion?-Carbohydrate =Role of pancreatic amylase and brush border enzymes
    -Protein =Role of proteases e.g. Trypsin and brush border enzymes
    -Fat =Role of lipases e.g. Triacylglycerol hydrolase
  84. 84What is Paracellular transport?-In paracellular transport substances diffuse between the adjacent cells of the epithelium
    -Paracellular pathway limited by tight junctions    What is Paracellular transport?
  85. 85What is paracellular transport limited by?What is paracellular transport limited by?
  86. 86What is transcellular transport?-In transcellular transport, substances move into an epithelial cell across either the luminal or basolateral surface, diffuse through the cytosol and exit across the opposite membrane
    -Carbohydrates, protein and fats are absorbed via transcellular transport    What is transcellular transport?
  87. 87What are the main sites of absorption in the GIT?What are the main sites of absorption in the GIT?
  88. 88How are carbohydrates absorbed?-Carbohydrate needs to be digested into single sugars Monosaccharides before absorption can occur
    -Transport proteins required
    -Glucose in transported via: Secondary active transport coupled
  89. 89How are carbohydrates digested/absorbed?How are carbohydrates digested/absorbed?
  90. 90What creates an ion gradient across the membrane?What creates an ion gradient across the membrane?
  91. 91How does the Na+/K+ ATPase work?How does the Na+/K+ ATPase work?
  92. 92What happens per cycle of activity of the Na+/K+ ATPases?3 x Na+ ions moved out of the cell -against its concentration gradient
    2x K+ ions moved into the cell -against its concentration gradient
    1 x molecule of ATP consumed in the process
  93. 93What is the function and location of the Na+/K+ -ATPase?What is the function and location of the Na+/K+ -ATPase?
  94. 94Diagram showing glucose absorption from intestine into bloodDiagram showing glucose absorption from intestine into blood
  95. 95What happens during low glucose?What happens during low glucose?
  96. 96A more detailed summary of how carbohydrates are digested/absorbedA more detailed summary of how carbohydrates are digested/absorbed
  97. 97How is protein absorbed?-Protein needs to be digested into single amino acids or di-peptides/tri-peptides before absorption can occur
    Transport proteins required
    -Amino acids are transported via Secondary active transport coupled to sodium

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University Physiology Organs Flashcards on GIT Physiology, created by Adrianna Bialecka on 01/04/2025.
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