MOD 2: Gastrointestinal (GI) System Infections

Plaque

A highly organized, spatially structured biofilm on the tooth surface

Calculus (Tartar)

Mineralized plaque that has hardened and must be professionally removed

Gingivitis

Gum inflammation characterized by redness, swelling, and easy bleeding

Periodontitis

Advanced disease where gums recede, deep pockets form, and bone loss can lead to loose teeth

Enteritis

Inflammation of the small intestine, typically causing watery diarrhea

Colitis

Inflammation of the large intestine (colon)

Dysentery

Severe colon inflammation resulting in blood and pus in the stool

Jaundice

Yellowing of skin/eyes because the liver cannot process bilirubin

Direct-Acting Antivirals (DAAs)

Drugs that target viral enzymes like RNA polymerase to cure Hepatitis C with >97% success

Microbial Intoxication (GI)

Food poisoning caused by eating pre-formed toxins, such as those from Staphylococcus aureus

Three antimicrobial components of saliva

IgA (neutralizes pathogens), Lysozyme (degrades cell walls), Lactoferrin (starves microbes of iron)

How S. mutans uses sucrose to cause cavities

Splits sucrose into glucose (builds biofilm/glucans) and fructose (fermented into lactic acid, erodes enamel)

How H. pylori survives stomach acid

Produces urease, converting urea into CO2 and ammonia; ammonia neutralizes the acid

Mechanism of cholera toxin

Increases cAMP, locking salt gates open; salt floods the gut, water follows by osmosis

Why antibiotics cause C. diff

Antibiotics destroy the protective normal microbiome, letting C. diff endospores germinate and flourish