Term
| What components of saliva inhibit bacterial growth? |
|
Definition
1) Glycoproteins
2) IgA, IgM, IgG
3) Lactoferrin
4) Lysozyme |
|
|
Term
| What does salivary glycoproteins do? |
|
Definition
| glycoproteins bind to bacterial receptors and prevent bacteria from binding to buccal epithelium |
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Term
| Where is Lactoferrin found? |
|
Definition
1) Saliva
2) breast milk
Released by:
1) epithelial cells
2)Neutrophils |
|
|
Term
| Describe the antimicrobial properties of Lactoferrin. |
|
Definition
Lactoferrin sequesters iron and by doing this deprives bacteria of iron.
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|
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Term
| To which bacteria is lactoferrin exhibit bactericidal properties? |
|
Definition
1) vibro Cholera
2) Pseudomonas aeruginosa
3) Ecoli |
|
|
Term
| What is the function of lysozyme? |
|
Definition
1) Split muramic acid in the wall of gram positive bacteria
2) works with lactoferrrin and bile salts to affect gram negative bacteria |
|
|
Term
| What components of gastric acid are antimicrobial? |
|
Definition
1) Pepsin
2) Lysozyme
3) HCL (particularly cholera) |
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|
Term
| How does Mucous protect the GI system from pathogens? |
|
Definition
| traps bacteria onto the epithelial surface |
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|
Term
| What are the components of mucus? |
|
Definition
1) 95% water
2) MUCIN-glycoprotein
3) phospholipids
4) lysozyme
5) lactoferrin
6) Bicarbonate (forms a pH gradient)
7) sIgA |
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|
Term
| What hormone stimulates the secretion of bile? |
|
Definition
|
|
Term
| What do unconjugated bile do? |
|
Definition
| inhibit growth of some anaerobes and some gram positive bacteria |
|
|
Term
| Who antimicrobial properties do conjugated bile (glycine, taurine) have? |
|
Definition
1) small intestine- inhibit bacterial overgrowth
2) Illeum- acids interact with FXR on epithelial which secrete NO and start cascade of events. |
|
|
Term
| What is the first step in gut colonization? |
|
Definition
ATTACHMENT!
1) gram + = fibronectin
2) cholera toxin = GM1 (Neu5Ac) |
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Term
| Why do people who are non-secretors have a higher incidence of clinical intestinal illness? |
|
Definition
| People who secrete antibodies in thier saliva, have antibodies that cross react with bacteria. These antibodies bind to bacteria and prevent them from entering further into the GI tract. |
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|
Term
| Why are individuals with type AB blood at low risk for cholera? |
|
Definition
| Vibro cholera antigens share reactivity with blood type A and B carbohydrates. |
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Term
| How do host epithelial cells and enterocytes provide an environment for attachment? |
|
Definition
1) epithelial cells have receptors (genetically determined)
2) enterocytes have glycocalyz (mucopolusaccharide) |
|
|
Term
|
Definition
1) recognize microbes
2) Cause an acute antimicrobial response
-antimicrobial peptides
-recruitment of inflammatory cells |
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|
Term
| Which antimicrobial peptides (AMPs) are found in the small intestine? |
|
Definition
1) alpha defensin
2) Besta defensin |
|
|
Term
| What cell produces alpha defensin? |
|
Definition
Paneth cells
(released through exocytosis) |
|
|
Term
| What cell stores alpha defensin? |
|
Definition
|
|
Term
| What is one theory of how alpha defensins work? |
|
Definition
1) induce pore formation and membrane instability
2) promote chloride secretion of epithelial cells
FLUSH out the bacteria from crypts!!! |
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|
Term
| Decreased production of alpha defenses results in |
|
Definition
|
|
Term
| What are the two types of alpha defensins? |
|
Definition
|
|
Term
| In what condition is alpha defensin HD-5 decreased? |
|
Definition
|
|
Term
| What can explain the high prevalence of disease in the illeum of patients with chrons disease? |
|
Definition
| Decreased production of alpha defensins produce bacterial overgrowth. These defensins are produced by paneth cells found in the small intestine. This is why many Chrons patients also lack the ability to kill Ecoli and Staphyloccocus aureus. |
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|
Term
| What do Paneth cells produce? |
|
Definition
1) Alpha defensins
2) Beta defensins (not restricted only to Paneth cells)
3) Lysozyme
4) Phospholipase A2
5) lectin (binds to carbs on peptidoglycan of gram+ bacteria-enterococcus fecalis) |
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|
Term
| Where can you find Human Beta defensins (hBDs)? |
|
Definition
All over the GI tract!
(expressed by enterocytes) |
|
|
Term
| Which beta defensin is not affected by proinflammatory cytokines? |
|
Definition
hBD1
nmemonic- number one came first before there were any proinflammatory molecules.
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|
|
Term
|
Definition
| migration of adjaacent epithelial cells upward after the epithelium is breached. |
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|
Term
| What cell produces trefoil factors? |
|
Definition
|
|
Term
| Where are the Trefoil factors found? |
|
Definition
1) TF1-gastric mucosa
2)TF2-bile and pancreatic ducts
3) TFF3- large and small intestine |
|
|
Term
| What is the function of Trefoil factors? |
|
Definition
| Maintains epithelial integrity by confering resistence to protease degradation. |
|
|
Term
| Where are the peyer's patches macroscopically visible and numerous? |
|
Definition
|
|
Term
| Which part of the intestine lacks goblet cells? |
|
Definition
1) GALT
(has instead membranous M cells that differentiate from enterocytes by factors released by lymphocytes) |
|
|
Term
| What is the function of the M cell? |
|
Definition
| Process a pathogen and present the antigen to basolateral APC (which presents it to the lymphocyte) |
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