digestive system

  1. What is the GI tract?
    Continuous tube from mouth to anus
  2. What are the 4 layers of the GI tract?
    • Mucosa (epithelium, lamina propria, muscularis mucosae)
    • Submucosa (lymph & blood vessels)
    • Muscularis (inner circular layer, outer longtitudinal layer)
    • Serosa (epithelium, arelora connective tissue)
  3. What are the accessory digestive organs?
    teeth, salivary glands, pancreas, liver, gallbladder, tongue
  4. what is the largest serous membrane in the body?
  5. pepsin
    digestive enzyme released by cheif cells in stomach, made in gastric mucosa (stomach), breaks down proteins into polypeptides
  6. bile
    produced by liver, stored in gallbladder, released into duodeum after fatty meal, helps emulsify fats so they can be broken down easier.
  7. lingual lipase
    in mouth, breaks down triglycerides into fatty acids and diglycerides
  8. pancreatic amalyse
    breaks down starches
  9. largest gland in body
  10. four stages of food processing
    ingestion, digestion, absoprtion, elimination
  11. what is deglutition
  12. pancreas
    produces secretions (panreatic juices) to aid digestion, had a head, body and tampering tail
  13. dual functions of pancreas
    • exocrine: secreates digestive juices (acinar cells) to buffer pH in gastric juices; stops pepsin working in stomach; digestive enzymes
    • endocrine: releases hormones (islet cells)
  14. liver portal triad
    hepatic portal vien, hepatic artery, bile duct
  15. liver functions
    • metabolism of carbs, lipids and proteins
    • process drugs and hormones
    • excrete bilirubin
    • synthesise bile salts
    • storage
  16. small intestine
    digestion and absorption; contains duodenum, jejunum, ileum
  17. what connects the small and large intestines?
    ileocecal sphincter
  18. cell types of small intestine
    goblet, absorptive, endocrine, paneth
  19. what do goblet cells secrete?
  20. what do absorptive cells do?
    absorbs nutrients
  21. gall bladder
    stores and concentrates bile and releases it into the small intestine
  22. liver, what does it produce
    bile, needed fro emulsification and absorptionof lipids in small intestine
  23. chyme
    patially digested food in small intestine
  24. small intestine function
    mix chyme with digestive juices: 90% nutirents and water absorbed here
  25. large intestine
    haustral churning, peristalsis, and mass peristalsis drive contents of colon into rectum
  26. all blood in digestive system passes through liver before entering the veinous system.
  27. where are most carbs broken down?
    Small intestine by pancreatic amylase
  28. what are the major regions of the large intestine?
    cecum, ascending, transverse, decending, sigmoid, rectum, anal canal, anus
  29. 3 phases of digestion
    cephalic phase: sight and smell of food, system gets ready; gastric phase, pH rises which triggers action in stomach; Intestinal Phase, food into small intestine
  30. 4 main endocrine hormones for GI tract
    • Gastrin
    • secretin
    • cholecystokinin
    • gastric inhibitory peptide
  31. gastrin
    released into blood by g cells in stomach in response to stomach distention, or activation of vagus nerve to stimulate pearietal cells in stomach to make HCL and intrincis factor
  32. secretin
    from s cells in duodenum, responds to acidic juices in stomach, stimulates pancreas to release HCO3
  33. cholecystokinin
    CCK cells in duodenum release CCk in response to fat and high protein, stimulates gallbladder to release bile, pancreas to release digestive enzymes
  34. gastric inhibitory peptide
    k cells in duodenum release GIP in response to fat adn carbs; slows entry to small intestine, stimulates insulin release from pancreas
  35. what are the 6 main types of nutrients
    • water
    • carbs
    • lipids
    • proteins
    • minerals
    • vitamins
  36. essential nutrients
    cannot be made in sufficient amounts, need to be ingested.
  37. metabolism
    all chemical reaction of the body
  38. enzymes
    catalyze chemical reactions
  39. anabolic reactions
    building reactions, endergonic -energy consuming
  40. catabolic reactions
    decomposition reactions, exergonic - produce energy
  41. carbs are broken down into
    • monosaccharides: glucose, fructose
    • these are then used to synthesize ATP, converted to glycogen or used to build trigylcerides
  42. what can gluose be converted into?
    several amino acids
  43. glycolysis
    anaerobic cellular repsiration
  44. krebs cycle
    energy transfer to coenzymes, series of oxidation reduction reactions, aerobic reactions
  45. Which reactions produce ATP during the complete
    catabolism of a molecule of glucose?
    Glycolysis, Krebs cycle, electron transport chain
  46. how many amino acids are there?
    20, 10 essential and 10 non essential
  47. what is a complete protein
    provides all 10 essential amino acids
  48. what is an essential amino acid?
    must be in diet, cannot be synthesized by body
  49. vitamins
    organic molecules required in small amounts, 13 essential
  50. what are the 2 groups of vitamins?
    • fat soluble (A,D,E,K)
    • water soluble (B and C)
  51. minerals
    simple inorganic nutrients, ie calcium, sodium, copper, potassium, sulfur, chlorine
  52. undernourishment
    result of a diet that consistently supplies less chemical energy than the body requires
  53. malnourishment
    the long term absence from the diet of one or more essential nutrients.
  54. What are the functions of segmentation and
    peristalsis in the small intestine?
    Segmentation- mixes chime with digestive juices and brings the chime into contact with the mucosa for absorption

    Peristalsis- pushes intestinal contents along the intestine
  55. What are brush border enzymes and what are their
    • Brush border enzymes, synthesised by absorptive
    • epithelial cells of the SI, function to digest carbohydrates, proteins and
    • nucleotides
  56. Describe the digestion of carbohydrates that occurs in the small intestine.
    Pancreatic amylase acts on glycogen and starches, then a brush border enzyme alpha-dextrinase continues enzymatic breakdown of carbohydrate by clipping off one glucose unit at a time.

    Other brush border enzymes digest disaccharides to monosaccharides; Sucrase digests sucrose into glucose and fructose, Lactase digests lactose into glucose and galactose; Maltase digests maltose into 2 glucose molecules.
  57. Why are bile salts needed for lipid digestion?
    • Bile salts emulsify large lipid globules into smaller
    • lipid globules which increases the surface area for pancreatic lipase to effectively digest triglycerides.
  58. The region of the stomach that surrounds the superior opening of the stomach is known as the
  59. This major duct carries a fluid rich in bicarbonate ions
    pancreatic duct
  60. This portion of the stomach connects to the duodenum
  61. When blood pH drops then the amount of oxyhemoglobin _______ and oxygen delivery to the tissue cells ________________.
    decreases, increases
  62. Which of the following enzymes digests proteins?
  63. not a function of the large intestine?
    Regulation of blood glucose
Card Set
digestive system
digestive system