Mod 7 - GIT

  1. Name 5 key charachteristics about the GI system
    • 1) series of hollow organs
    • 2) separated by sphincters
    • 3) specialized secretions
    • 4) characteristic layered structure
    • 5) dibgestion consists of mechanical and chemical processes
  2. Name 2 purposes for uptake of nutrients
    • 1) energy replenishment
    • 2) building blocks for metabolism (essential AA, fatty acids, minerals, vitamins)
  3. What is the difference between hunger/satiety and appetite?
    hunger/satiety: regulates energy intake

    appetite: regulates specific nutrient intake
  4. Name some stimulatory and inhibitory regulators of food intake
    stimulatory: ghrelin (released by stomach during fasting)

    • inhibitory:
    • stomach stretch receptors;
    • CCK, insulin, and PYY (gastro-intestinal hormones)
    • leptin (released by growing fat cells)
  5. What factors control the conditions in the lumen of the GIT?
    • 1) food motility
    • 2) secretion of enzymes
    • 3) acidity
  6. Describe parasymp innervation of the GIT
    Vagus: esophagus, stomach, pancreas, a little to SI and LI, stimulates ENS

    Sacral nerves: distal half of LI, anus, defecation reflexes
  7. Describe sympathetic innervation of the GIT
    celiac ganglion and the meseteric ganglion

    innervate all parts

    release norepinephrine which inhibits peristalsis and increases sphincter tone
  8. List 4 major GI hormones
    gastrin: released by stomach (releases HCL, increase intestine movement, release of pepsinogen)

    Secretin: released by SI, pancrease secretes alkaline, pro-enzyme, stimulates intestinal motility

    CCK: secreted by SI, secretion of proenzymes and bile

    Gastric Inhibitory Peptide: insulin secretion, inhibits gastric secretion and motility
  9. Describe the 3 phases of digestion regulation
    1) celiac: you know food is coming, increased salivation and blood flow, stomach motility inhibited, initiates secretions

    2) Gastric phase: food is in stomach, increases blood flow, increases SM stimulation, secretion of bile, panc juices, intestinal juices, intestinal mobility

    3) Intestinal phase: chyme in duodenum, inhibits stomach to prevent overloading, secretion of bile, panc juices, intest. juices, increase blood flow to intest., gallbladder constriction and relaxation of sphincter of Oddi
  10. List the muscles of the abdominal wall
    Superficial to deep: Rectus abdominus, external oblique, internal oblique, transverse
  11. List the layers of the lateral abdominal wall
    • Superficial to deep:
    • skin, Camper's fascia, external oblique, internal oblique, transverse abdominal, transversalis fascia, parietal peritoneium
  12. what is the linea semilunaris
    semilunar line that marks the border of the rectus abdominus
  13. List the layers of the anterior abdominal wall
    skin, camper's fascia, external oblique apon., internal oblique apon., rectus abd., internal oblique apon., transvers abd. apon., transversalis fascia, parietal perit.
  14. What are the components of the inguinal region?
    • inguinal ligament
    • inguinal canal
    • spermatic cord (round ligament in females)
  15. What ate the contents of the spermatic cord?
    • Vas def.
    • testicular a (off aorta)
    • testicular v
    • lymphatics
    • Cremaster muscle (raise and lower testes based on temp)
    • sympathetic fibres
    • genital branch of genitofemoral n
  16. What is the difference between direct and indirect inguinal hernias?
    indirect: enters deep inquinal ring, exits superficial inguinal ring, can cause strangulation

    direct: inters in Hasselbach's triangle and exits superficial inguinal ring, more common in old men, less serious
  17. What does each saliva gland secrete
    • parotid: watery, little mucus, amylase-rich
    • submadibular: high in lysozyme
    • lingual: mixed
  18. What are the functions of saliva
    • lubrication
    • amylase (breaks down starch)
    • protective functions (mucins coat, acts as a buffer, control of water intake (dry mouth), antimicrobial, drug absorption
  19. Describe ho saliva is secreted
    • 1) liquid comes from capillary
    • 2) acinar cells add mucin, amylase, etc
    • 3) primary secretion is isotonic with plasma
    • 4) duct cells remove Na and add K (more K is added therefore secretion becomes more hypotonic)
    • 5) add bicarbonate and remove CL AND Vice versa
  20. Describe the three phases of swallowing
    • 1) voluntary phase: tongue moves bolus to back of mouth
    • 2) pharyngeal phase: bolus activates pressure sensors, triggers reflexes in teh swallowing centers of the brain stem. close epiglottis, esophagal sphincter opens
    • 3) esophagal phase: peristaltic wave. Primary wave is goes from pharynx to stomach, secondary waves continue in esophagus (if necessary) until food is all in stomach
  21. list the major cells in the gastric glands in the corpus
    • 1) parietal cells (acid and intrinsic factor)
    • 2) chief cells (pepsinogen)
    • 3) mucous cells (secrete mucus, bicarbonate, sodium)
    • 4) enterochromaffin-like (ECL) cells secrete histamine
  22. List the major cells in the gastric glands in the antrum
    • 1) cheif cells (pepsinogen)
    • 2) endocrine cells (gastrin, somatostatin)

  23. What are the 4 phases of acid secretion?
    • 1) basal state: low rate, huge variation between individuals, low pH (no buffers)
    • 2) Cephalic phase (food is coming): stimulates vagus nerve, stimulates H+ and gastrin, inhibits somatostatin (30% of secretion)
    • 3) Gastric phase: distension of stomach stimulates vagus, dig protein activates antral G cells (gastrin) (50-60% of secretion)
    • 4) Intestinal phase: intestinal cells and absorbed AA's cause small amount of secretion (5-10%)
  24. describe how the duodenum regulates stomach empyting based on the type of meal
    • water/saline: leaves quickly
    • acid meal: takes longer
    • presence of lipids: takes even longer

    Makes sure the duodenum doesn't get overloaded.
  25. Some side effects of gastric bypass surgery
    • B12 deficiency
    • can't convert Fe3 to Fe2
    • need to regulate food intake
  26. How do pancreatic ducts cells make bicarbonate?
    • 1) tubulovesicles have H+ pumps
    • 2) t. vesicles move to the basilar membrane when duct cell is activated
    • 3) pump H+ into the blood and HCO3- into the cell and ultimately into the duct.
  27. Discuss how proteins, carbs, and fats are broken down in the duodenum.
    • proteins: trypsin, chymotrypsin, carboxypolypeptidase
    • carbs: pancreatic amylase
    • fat: pancreatic lipase, phospholipase, others
  28. Describe the different types of diarrhoea
    -secretory: oversecretion of water, absorption cant cope, caused by bacterial toxins or overstim. of ENS

    -defective ion transport: fat malapsorption, bile acids, diabetes, inflammatory mediators like histamine

    -osmotic diarrhoea: hyperosmotic fluid in lumen, fermentation can cause hyperosmotic

    -hypermotility of intestines: bacterial toxins
  29. List the hormones that affect peristalsis and motility
    Increase motility: CCK, secretin, gastrin,

    Increase peristalsis: motilin (hormone relseased after chyme turns alkaline)

    Decrease peristalsis: enteroglucagon (when glucose and fat in chyme)
  30. describe the gastro-ileal reflex
    • -fluidity of contents promotes emptying
    • -pressure and chem irritation in ilium increase peristalsis and relaxes sphincter
    • -pressure or chem irritation in cecum inhibits peristalsis and excites sphincter
  31. What happens to carbs after they are absorbed
    • 1)Sent to liver
    • 2) liver converts fructose and galactose to glucose
    • 3) glucose released back into blood
    •   -enters cells for glycolysis and citric acid cycle
    •   -liver converts to glycogen (skeletal muscle) and TAG (adipose tissue)
    •   -
  32. What are the three sources of energy for adipose tissue?
    • glucose
    • very LDL's (from liver)
    • chylomicrons

    All stored as TAGs
  33. What organs drain into the portal venous system
    stomach, spleen, small intestine, pancreas, large intestine
  34. What is jaundice?
    lots of bilirubin in the blood (bile reflux into blood). Urine is dark because of conjugate bilirubin excretion.
  35. What are gall stones?
    Cholesterol stones: cholesterol precipitates in gall bladder. Due to chronically high bile acid : lecithin (phospholipid) ratio. Increased risk in women. low bile salts.

    Pigment stones: overload of unconjugated bilirubin
  36. Describe the three types of oral mucosa
    1) lining (red) flexible: over loosely fibrous LP, not many dermal papillae. Found: soft palate, inside lips and cheeks, ventral tongue, over alveolar bone (except where it is gingiva)

    2) Masticatory (pink) immobile: in contact with food, keratinized or para keratinized, found: gingiva, hard palate

    3) Specialized: aterior 2/3 of dorsum of tongue, may be keratinized has papillae.
  37. Describe the 4 types of lingual papillae:
    1) filliform: heavily keratinized, no taste buds, why we brush our teeth.

    2) Circuvallate papillae: taste buds flushed by von Ibner's glands, may be keratinized

    3) fungiform papillae: not keratinized, taste buds on surface, 

    4) foliate papillae: no keratinized, taste buds on lateral wall
  38. Describe the secreting cells in salivary glands
    Serous (red, look like pizza slice): secretes watery or albuminous fluid

    Mucous (look like adipocyte): secrete mucus
  39. Discuss the ductal system in the pacreas
    • 1) centroacinar cells: beginning of duct
    • 2) intercalated duct: secrete sodium and bicarbonate, stimulated by secreting
    • 3) intralobular
    • 4) interlobular
    • 5) pancreatic duct
  40. Discuss the cells of the liver
    -Hepatocytes: 80% of liver vol, many microvilli facing blood plasma (in space of Disse), cell surface of adjacent cells form microscopic channels called bile canaliculi, lots of breakdown (therefore lots of RER)

    • -Ito cells: may form part of sinusoid wall, make vit A, make most of liver's CT, can diff into myofibroblasts
    • -Kupffer cells: macrophage, also form wall of sinusoid, degrade old RBCs, filter the lumen

    -sinusoidal epithelial cells: form a fenestrated epithelium, line the sinusoid, BM forms outer wall of the space of Disse 

    -pit cells: NK cells,
  41. Describe the three ways to describe liver lobules
    Image Upload 1
  42. Describe the basic structure of the GIT
    • -Mucosa:
    •   -3 layers (epithelium, lamina prop (BV's and lymphocytes), muscularis mucosae(gentle agitation));
    •   -4 types (protective, secreting, absorptive, absorptive/protective)

    -Submucosa: strongest layer in gut; Meissner's plexus, glands in esophagus and upper duodenum

    -muscularis externa: long and circular muscle, myenteric nerve plexus

    -serosa, adventitia:
  43. What factors affect liver enzyme levels in plasma or serum?
    • 1) entry of enzymes into blood (leakage, production)
    • 2) efflux of enzymes from damaged cells
    • 3) clearance of enzymes
  44. Describe what liver enzymes you expect to see in hepatocellular disease, biliary tract disease
    HC disease: elevated AST, ALT, LD

    BT disease: elevated ALK, GGT, 5'NT

    Observe relative increase over Upper Limit of Normal (ULN)
  45. Describe what happens to AST and ALT levels in hepatitis and necrosis of hepatocytes
    viral hepatitis (acute): cell damage causes release of cytoplasmic AST and ALT (ALT>=AST)

    Necrosis of hepatocytes: release of both cytoplasmic and mitochondrial AST and ALT (AST>ALT)

    chronic alcoholism: AST>ALT (>2:1)

    Recall that there is lots of AST in the mitochondria, not so much for ALT
  46. Name some common causes of acute hepatocellular injury
    • All three hepatitises
    • Alcoholic hepatitis
    • toxic injury
    • ischemic injury
  47. List 4 major sources of ALP, how would you determine if elevated ALP was due to a liver problem?
    Sources: liver, bone, placenta, ilium

    Check and see if GGT or 5'NT are also elevated
  48. What do bacteria in the gut do?
    • -riboflavin, thiamin, B12, K are made
    • -fermentation of cellulose
    • -recirculation of bile salts
    • -prevent growth of harmful bacteria
  49. List the cells found in a gastric gland (fundus/body)
    • -surface and neck mucous cells
    • -stem cells
    • -Chief cells (pepsinogen and lipase) - apical granules
    • -Parietal cells (HCl and intrinsic factor) - proton pumps in tubulovesicles (bigger than chief)
    • -enteroendocrine cells: secretes hormones into lamina propria
  50. Where does the stomach mucous blanket get bicarbonate from?
    • surface cells
    • fenestrated capillaries that pick it up from the basal side of parietal cells
  51. Describe the epithelial cells found in the SI
    • -enterocyte: absorptive cell, glycocalyx on microvilli
    • -goblet cells: mucous
    • -enteroendocrine cells: secerete gastrin, somatostatin, CCK, secretin, others
    • -paneth cells: at base of cells, innate immune system
    • -M cells: antigen-presenting cells
    • -stem cells (in crypts): make other cells
  52. Describe the three regions of the SI
    duodenum: brunner's glands, sphincter of Oddi,  intestinal glands (=crypts)

    Jejunum: long and finger-like with well-developed lacteals

    Ilium: Peyer's patches (lymphoid tiss., capped by M cells), shorter villi
  53. What causes obesity?
    • genes
    • lifestyle
    • abnormal feeding
    • childhood overnutrition
  54. Describe some drug treatments for obesity
    • amphetamines: inhibit feeding centres
    • Sibutramine: inhibit feeding centres and increase metabolism
    •   -both of these overexcite the CNS
    • Orlistat: lipase inhibitor (you will just poop out lipids)
    • Gastric bypass surgery: decrease amount of food being eaten.
  55. Define the following: Inanition, anorexia, anorexia nervosa, cachexia, bulemia nervosa, ednos
    • Inanition: extreme weight loss
    • anorexia: diminished appetite
    • a. nervosa: abnormal psychic state with aversion to food
    • cachexia: abnormally high metabolism
    • bulemia nervosa: highly irregular feeding pattern with NO extreme weight loss
    • Ednos: extreme preoccupation with weight.
  56. Describe the 4 lobes of the liver
    • Right
    • Left
    • quadrate (anterior)
    • Caudate (posterior)

    • 1st 2 separated by the falciform lig
    • last 2 on inferior surface of liver
  57. List the 4 portal-systemic anastomoses
    • esophageal
    • peri-umbilical
    • colic
    • rectal
  58. Describe diverticular disease
    out-pouchings of intestinal mucosa

    -usually asymptomatic: can rupture causing BRB to be in stool, other minor GI symptoms

    -may also become infected like an appendix
  59. Describe colon cancer
    symptoms: abdom. pain, change in stool habits, weight loss, anorexia, fatigue, occult bleeding, BRB, may be palpable

    treatment: combination of surgery and medical care
  60. Why do a digital rectal exam?
    • males: prostate, deep lymph nodes, 
    • females: internal genitalia, pelvic bones, deep LNs

    both: rectal tumors, occult blood
Card Set
Mod 7 - GIT
Mod - GIT