Gastrointestinal Flashcards

1
Q

4 layers of the GI tract

A

Mucosa: epithelium, lamina propria, muscularis mucosae
Submucosa: glands, blood vessels, nerves
Muscularis propria/externa: inner circular and outer longitudinal muscle layer
Adventitia/Serosa

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2
Q

Circumvallate papillae

A

Dome-shaped
Sunken structures
8-12 of them
Taste buds

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3
Q

Filiform papillae

A

Small conical prominences on lingual surface

No taste buds

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4
Q

Fungiform papillae

A

Mushroom shaped projections on the surface among the filiform but mainly at the tip and lateral margins
Have taste buds on the upper surface

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5
Q

Foliate papillae

A

Short vertical folds on the lateral margins
Taste buds scattered over the surface
Serous glands drain into the fold and clean the taste buds

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6
Q

How many teeth do children vs adults have?

A

Children: 20
Adults: 32

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7
Q

3 major salivary glands

A

Parotid
Sublingual
Submandibular

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8
Q

Function in the salivary glands

  1. Serous cells
  2. Intercalated duct cell
  3. Striated duct cell
A
  1. Secrete amylase - digests starch into maltose
  2. Secretes bicarbonate, absorbs Cl-
  3. Modifies saliva to be hypotonic with plasma
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9
Q

Upper 1/3 of esophagus is…

A

Striated muscle! Voluntary

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10
Q

GERD

A

Gastrointestinal reflux disease
Lower esophageal sphincter fails to close properly
Stomach contents leak back, reflux
Can taste stomach fluid in the back of the mouth
Frequent heartburn

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11
Q

Eosinophilic Esophagitis

A

Inflammation or swelling of the esophagus
Diagnose with endoscopy and biopsy
Large number of eosinophils cause inflammation
Stiffening or narrowing of the esophagus
Can lead to difficulty swallowing (dysphagia)

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12
Q

3 types of stomach glands

A

Cardiac glands
Pyloric glands
Gastric/fundic glands

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13
Q

4 types of cells in the stomach glands

A

Mucous cells
Parietal cells or oxyntic cells
Chief cells
Enteroendocrine cells

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14
Q
What do
1. Mucous cells
2. Parietal cells or oxyntic cells
3. Chief cells
4. Enteroendocrine cells
secrete?
A
  1. Secretes mucus into the lumen
  2. Secretes HCl, intrinsic factor into lumen and bicarbonate into blood
  3. Pepsinogen (zymogen, gets converted to pepsin) into lumen
  4. hormones - G cells secrete gastrin into blood
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15
Q

How is the stomach unique?

A

Has 3 layers of muscle (oblique muscle is extra)

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16
Q

Barrett’s esophagus

A

Stratified squamous epithelium of the esophagus is replaced by simple columnar epithelium with goblet cells
Strong association with esophageal adenocarcinoma

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17
Q

Brunner’s glands

A

Only in the small intestine (submucosa)

Secrete alkaline fluid containing neutral and alkaline glycoproteins and bicarbonate ions

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18
Q

Crypts of Liberkuhn

A

Secrete carbohydrases, proteases, and lipases

In the mucosa

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19
Q

4 principle cell types in the small intestine

A

Enterocytes
Paneth cells
Goblet cells
Enteroendocrine cells

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20
Q
What do
1. Enterocytes
2. Paneth cells
3. Goblet cells
4. Enteroendocrine cells
secrete?
A
  1. Digest and absorb things
  2. Secrete lysozyme and defensins into lumen
  3. Mucus into lumen
  4. Secretin, CCK, GIP, others into blood
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21
Q

Period acid-Schiff stain

A

Used to detect polysaccharides such as glycogen, and glycoproteins, glycolipids, and mucins

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22
Q

Endopeptidases

A

Cleave the polypeptide at interior bonds

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23
Q

Exopeptidases

A

Cleave the terminal amino acid

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24
Q

2 subclasses of exopeptidases and where they cut

A

Aminopeptidases: cleave off the terminal amino acid at the amine end of the chain
Carboxypeptidases: cleave off the terminal amino acid at the carboxyl end of the chain

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25
Q

Colipase

A

Binds to the lipidase and enhances its activity by anchoring to the lipid-water interface
Free fatty acids and monglyceride are generated, which combine with other lipids and bile salts to form water-soluble micelles

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26
Q

Zonula occludens

A

Tight junctions
Proteins are occludins and claudins
Most important barrier in making it tight
Most apical

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27
Q

Zonula adherens

A

Adherens/intermediate junctions, belle desmosome
Cadherins (homophilic) - bind to each other
Catenins are linked to cellular actin

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28
Q

Desmosomes

A

Macula adherens
Cadherins and desmoplakin linked to intermediate filaments
Junction communicates with the skeleton of the cell

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29
Q

Plicae circulares

A

In the small intestine
Folds of the mucosa into the lumen (has crypts and villi)
Even more surface area

30
Q

Glycocalyx

A

Acidic mucopolysaccharides and glycoprotein matrix on the apical surface, on the microvilli

31
Q

Gastrin

secreted by, source and stimulus, target organ, response

A

S: stomach mucosa
SS: stomach in response to food
TO: stomach, small intestine
R: release of HCl, increase of intestine movement, release of pepsinogen

32
Q

Secretin

secreted by, source and stimulus, target organ, response

A

S: Small intestine
SS: duodenum in response to acidic chyme
TO: pancreas
R: secretion of alkaline digestive proenzyme, inhibits intestine motility

33
Q

Cholecystokinin
(secreted by, source and stimulus, target organ, response)
More details

A
S: Small intestine
SS: intestinal cells in response to food
TO: pancreas, gallbladder
R: secretion of proenzymes and bile
Secreted by I cells in the epithelium
Inhibits gastric emptying and gastric acid secretion, stimulates acinar cells of the pancreas to release digestive enzymes, increased production of bile, contraction of the gall bladder, relaxation of the sphincter so bile can enter duodenum
34
Q

Gastric Inhibitory Peptide

secreted by, source and stimulus, target organ, response

A

S: Small intestine (K cells)
SS: Intestinal cells in response to fat
TO: stomach, pancreas
R: insulin secretion, inhibits gastric secretion and motility
Actions on fat cells and bone remodelling

35
Q

Haustr

A

Pouches formed by the taenia coli

36
Q

Taenia coli

A

3 independent long ribbons of smooth muscle just below the serosa, along the colon length
Condensations of the longitudinal muscle layer

37
Q

Cecum functions

A

Salt recovery (uptake)
Lubricates sold waste
Bacterial digestion of cellulose

38
Q

Appendix

A
Same histology as the rest of the intestine
Small blind ending pouch from the cecum
Thickened walls (due to lymphoid tissue)
Longitudinal smooth muscle layer does not aggregate into taenia coli
39
Q

4 different kinds of epithelium and their location in the large intestin

A

Simple columnar epithelium in the upper zone
Stratified squamous epithelium in the middle and lower zones
Simple columnar epithelium of the anal glands
Stratified columnar epithelium of the anal sinuses, crypts, and ducts of the anal glands

40
Q

Myenteric Plexus

A

Aka Auerbach’s plexus

Major role in motility and passing food through the digestive tract

41
Q

Submucosal Plexus

A

Aka Meissner’s plexus
A secondary plexus
Derived and formed by branches that have perforated the circular muscle
Innervates the epithelial layer and muscularis mucosae

42
Q

Celiac disease

A

Genetic predisposition to an autoimmune, crossreactive reaction to gluten (modified by transglutaminase)
Pale, loose and greasy stool affecting absorption
Range from almost asymptomatic to very bad malnutrition

43
Q

Lactose intolerance

A

Lack of lactase (cleaves lactose into glucose and galactose)
Results in high concentrations of lactose reaching the colon and affecting the osmotic state, passively drawing water into the lumen
Normally the amount of lactase declines with age

44
Q

Colitis

A

Inflammation of the colon
Multiple causes
Abdominal pain and diarrhea

45
Q

Chron’s vs ulcerative colitis

A

C: inflammation affects the alimentary tract
UC: inflammation affects colon and rectum

46
Q

Irritable bowel syndrome

A

Non-inflammatory symptom based diagnosis

Chronic abdominal pain, discomfort, bloating, and diarrhea/consitpation

47
Q

Diverticulosis

A

Small weak areas in the colon wall allowing the mucosa to protrude through, forming tiny pouches called diverticuli
Usually no problem but can bleed, become inflamed or infected to become diverticulitis

48
Q

Colon polyps

A

Familial adenomatous polyposis
Small growths
Some develop into cancer over a long time

49
Q

Occult vs frank blood

A

O: high GI bleed
F: low GI bleed

50
Q

Triad in portal area

A

Hepatic artery
Bile duct
Portal vein

51
Q

Sinusoids

A

Low pressure channels that receive blood from terminal branches of hepatic artery and portal vein and deliver it to central canal
Lined with fenestrated endothelial cells and flanked by hepatocytes

52
Q

Space of Disse

A

Between endothelium and hepatocytes

Plasma accumulates and retrogradely flows back into the lymphatics

53
Q

Kupffer cells

A

Type of macrophage that engages bacteria coming from the intestine
In the sinusoids
Deal with foreign particles (gut endotoxins)

54
Q

Stellate cell

A

Between sinusoid and hepatocytes (in space of Disse)

Make collagen fibrils and ECM materials

55
Q

Hepatocyte function

A
Bile production, uptake and transport
Lipid uptake and metabolism
Glycogen synthesis
Detoxification by p450 enzymes
Protein synthesis (ex: albumin, complement, fibrinogen, lipoproteins)
56
Q

2 functions of bile

A

Emulsification of lipid aggregates

Solubilization and transport of lipids

57
Q

Hering’s canal

A

Vessels collecting bile from the canaliculli

58
Q

Bile ducts

A

Collect bile from Hering’s canals

Parallel to hepatic arteries and portal veins

59
Q

Common hepatic duct

A

Collects bile from hepatic ducts and branches into the cystic duct and then the common bile duct which then empties into the duodenum

60
Q

Jaundice

A

Increased bilirubin in the blood

61
Q

Cirrhosis

A

Normal liver cells are replaced by scar tissue due to chronic liver disease
Alcohol abuse most common

62
Q

Steatosis

A

Fatty liver disease

Cholesterol or TAGs accumulate

63
Q

Types of exocrine cells in pancreas

A

Acinar: secretes digestive enzymes
Ductal: secrete bicarb

64
Q

Types of endocrine cells in pancreas

A

Alpha cells: glucagon
Beta: insulin
Delta: somatostatin

65
Q

Action, precursor and activator for:

  1. Trypsin
  2. Chymotrypsin
  3. Elastase
  4. Carboxy’dase A/B
A
  1. Endopeptidase, trypsinogen, enteropeptidase/enterokinase and trypsin
  2. Endopeptidase, chymotrypsinogen, trypsin
  3. Endopeptidase, proelastase, trypsin
  4. Exopeptidase, procarboxy’dase A/B, trypsin
66
Q

What activates enteropeptidase?

A

Duodenase

67
Q

Somatostatin

A

Produced by delta cells in the pancreas

Reduces smooth muscle contractions in tract and gall bladder

68
Q

Pancreatic insufficiency

A

Lose about 90% ability to secrete digestive enzymes
Patients unable to digest food, resulting in malabsorption of nutrients (including vitamins)
Impaired absorption of fats causes diarrhea, weight loss, malnutrition

69
Q

Cystic fibrosis

A

Loss of the CFTR
Decreased production of sodium bicarbonate makes secretions dehydrated, thickened, blocking ducts
Pancreas continues to make enzymes that damage it, leading to fibrosis

70
Q

Peyer’s patches

A

Mucosal inductive site
Where the cells become stimulated
Have M cells

71
Q

Intraepithelial lymphocyte

A

Function is not entirely clear
Likely play a role in detecting pathogens or react to infected or damaged (and cancerous) epithelial cells
Have cytotoxic properties so are able to kill abnormal cells

72
Q

Histatins

A

Antifungal properties

Made in salivary glands