Gut Flora

Question 1

Why does the upper gut have low gut flora populations?

Answer 1

Gastric acidity
Propulsive motility
Pancreatic enzymes

Question 2

What factors of the large intestine allow a large and complex ecosystem of gut flora to develop?

Answer 2

Stagnant motility with retropulsive contractions

pH buffered by bicarbonate ions

Question 3

How many different species of bacteria exist in the large intestine?

Answer 3

Over 400

Question 4

What is the importance of gut flora?

Answer 4

They have roles in nutrient metabolism, xenobiotic and drug metabolism, antimicrobial protection and immunomodulatiom

Question 5

Gut bacteria are mostly strict anaerobes. T/F?

Answer 5

True

Question 6

Approximately what mass of undigested carbohydrate is fermented by gut bacteria every day?

Answer 6

60g

Question 7

Bacteria in the large intestine can ferment carbohydrates to produce short chain fatty acids including acetic acid, propionic acid and butyric acid. Why are these useful?

Answer 7

Acetic acid is a substrate for fat synthesis in the liver
Propionic acid is used as an energy source for the liver, is gluconeogenic and may reduce cholesterol synthesis
Butyric acid is a major energy source for colonic cells and can stimulate differentiation of colonic cells and can massively stimulate sodium and chloride ion absorption