Microbiota of the Gut Flashcards Preview

Yr2 Alimentary > Microbiota of the Gut > Flashcards

Flashcards in Microbiota of the Gut Deck (15)
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1
Q

What conditions alter microbial populations throughout the GI tract?

A

Transit Time
Oxygen presence
pH

2
Q

How does transit time affect the gut microbiota?

A

Slow growing bacteria wont grow in a gut section with a rapid transit time

3
Q

How does O2 affect gut microbiota?

A

The population of the gut changes from faculative anaerobes –> Obligate Anaerobes as the gut gets more anaerobic

4
Q

How does pH affect the gut microbiota?

A

Different sections of the gut are at different pH’s

Therefore bacteria which thrive on different pH’s grow in different areas of the gut

5
Q

What are the functions of the GI microbiota?

A
  • Metabolise dietary components/produces essential metabolites
  • modify host secretions e.g. mucins and bilirubin
  • Defends against pathogens
  • Immune system priming
  • Host signalling
6
Q

How does the gut microbiota protect against pathogens?

A

Direct Competition - Produces active compounds that kill incoming pathogens

Priming the immune system - Training the immune system to fight bacterial infections

Barrier Function - Literally provides a physical barrier to pathogens colonising the gut

pH Inhibition - Most pathogens grow at pH’s over 6. Bacteria break down cellulose to SCFAs (mainly in the colon) which lowers the pH and inhibits pathogen growth

7
Q

Why is the presence of bacteria important for the gut?

A
  • They prevent pathogenic bacteria colonising you
  • Dysbiosis of the gut microbiota can disrupt the homeostasis of the gut and lead to inflammation
  • Metabolites of the microbiota are important for energy, signalling molecules and maintaining the immune system
8
Q

How do antibiotics affect the microbiota?

A

Most are fairly broad spectrum so kill a lot of commensal bacteria resulting in a loss of diversity which leads to issues:

  • Processing your diet
  • Pathogenic Infection
  • Maintaining the immune system
  • Signalling molecules
9
Q

How do antibiotics cause pathogenic infection of the gut?

A

antibiotics wipe out a lot of commensals

  • > Opportunistic pathogenic infection, (often antibiotic resistant)
  • > Toxins, abdominal pain, diarrhoea, fever etc (often CDAD)
  • > Has to be treated with antibiotics
  • > Viscous circle of recurrent infections
10
Q

CDAD?

A

Clostridium Difficile Associated Diarrhoea

11
Q

How do we treat dysbiosis of the gut microbiota?

A

A Faecal Microbial Transplant which essentially inserts the right commensal bacteria back in to begin rebuilding the gut microbia.

12
Q

Do we have more microbial cells or human cells?

A

Microbial cells on/in our body well outnumber our own cells

13
Q

What part of the GI tract is the most populated?

A

The large intestine, predominantly by anaerobic bacteria

14
Q

What lifestyle factors change your microbiota?

A

Diet and Age

15
Q

What is dietary fibre for?

A
Large intestine bacteria ferments dietary fibre.
The metabolites (e.g. SCFAs) are important for health and have distant effects far outside the gut by circulating through your blood