Lecture 33 - Digestive System Disorders Flashcards
Why is the native flora of the mouth different from that of the small intestine and colon?
Native flora in small intestine and colon are coated in mucin. Stimulates IL-10 and inhibits IL-2
What steps lead to dental caries?
I. Streptococcus mutans forms a biofilm in presence of sucrose.
II. Acid fermentation lowers the oral pH
III. enamel dissolves below 5.5
Where does Helicobacter pylori live? How does it make you sick?
It is native to the stomach flora
It thins the mucus lining so the stomach acid will erode the epithelial tissue. Leads to formation of ulcers
Name two virulence factors associated with H. pylori
produces urease and VacA toxin
How does cholera toxin produce symptoms of cholera?
B part bind epithelial cell receptors
A part ADP-ribosylates a regulatory protein which leads to excess cAMP secretion into gut.
Symptom is diarrhea, or rice-water stool.
How is cholera transmitted?
ingestion of seafood/copepods or drinks from fecal-contaminated water
How can you avoid cholera?
“boil it, peel it, cook it, or forget it”
only drink bottled water
How can you treat cholera?
administer “oral rehydration salts”
What are the symptoms of dysentery (enteritis)?
cramps and diarrhea with blood
What causes dysentary?
- Shigella
- E. coli
- Campylobacter
- Salmonella
Differentiate between Salmonella and Shigella infection mechanisms
Both taken up via M cells
Shigella produces shiga toxin and uses actin tails to travel
Salmonella enters macrophages
Name an autoimmune sequela associated with enteritis caused by Campylobacter
Guillain Barre Syndrome which is demyelination of the nerves
Differentiate between typhoid fever and Salmonella enteritis
Salmonella enters macrophages and causes diarrhea
Typhoid fever is when it disseminates in the blood and colonizes the gallbladder
What are the symptoms of mumps and why they are worse in adults than in kids
causes tissue swelling which is especially bad in testicle and ovary organs
How have sound epidemiological practices prevented a Mumps outbreak in the Midwest?
Identified and quarantined (5 days) the first case and their network.
Also gave MMR vaccinations
Differentiate between rotavirus and norovirus with respect to symptoms and at-risk population?
rotavirus: infects children and causes diarrhea
Norovirus: infects adults (that eat shellfish) and causes diarrhea, nausea, vomiting
Transmission of Hepatitis viruses
A and E are foodborne (fecal-oral)
B, C, D are spread by sex, needles, sharing razors, or toothbrushes
Symptoms of Viral Hepatitis
I. Jaundice
II. Abdominal Pain
III. Fatigue
IV. Nausea
V. Diarrhea
What is the unique replication mechanism of Hep B virus
It uses an RNA intermediate & own reverse transcriptase to make new DNA
How do you prevent the various types of hepatitis?
A: inactivated vaccine
B: recombinant vaccine
C-E: no vaccine
What are the symptoms of Giardia?
“explosive’ foul-smelling diarrhea and gas
greasy stool
How do you avoid and treat Giardia?
filter all drinking water on hiking trips or boil it
treat with metronidazole
What are the symptoms of Cryptosporidium?
cramps and water diarrhea
What is the biggest Crypto outbreak in history?
Milwaukee water facility incident
How does the life-cycle of Entamoeba histolytica cause the symptoms of amoebic dysentery?
