The Microbiota of the GI Tract 1 Flashcards Preview

07. Year 2: Alimentary System > The Microbiota of the GI Tract 1 > Flashcards

Flashcards in The Microbiota of the GI Tract 1 Deck (74)
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1

What is the transit time in the mouth?

1 minute

2

What is the transit time in the oesophagus?

4-8 seconds

3

What is the transit time in the stomach?

2-4 hours

4

What is the transit time in the small intestine?

3-5 hours

5

What is the transit time in the colon?

10 hours to several days

6

What does transit time affect?

Bacterial populations due to different bacterial growth rates

Intestinal cell exposure to toxins, consumed with food or produced by bacteria

7

How does the amount of bacteria change as you go down the GI tract from the stomach to the colon?

Increases

8

What does anaerobic mean?

Living in the absence of oxygen

9

What does aerobic mean?

Living in the presence of oxygen

10

What are different classes of anaerobic bacteria?

Facultative anaerobic bacteria

Obligate anaerobic bacteria

11

What are facultative anaerobic bacteria?

Can grow in the presence of oxygen and in the absence of oxygen (some grow poorly when oxygen is present)

12

What are obligate anaerobes?

Cannot grow in the presence of oxygen (many rapidly killed in the presence of oxygen)

13

What are examples of bacteria found in the stomach?

Lactobacillus

Candia

Streptococcus

Helicobacter pylori

 

14

What are examples of bacteria found in the colon?

Bacteroides

Clostridium

Bifidpbacterium

Enterobacteriaceae

15

What class of anaerobes are found in the stomach?

Faciltative anaerobes

16

What class of anaerobes is found in the colon?

Obligate anaerobes

17

Why do different kinds of bacteria dominate different areas of the GI tract?

Different oxygen concentrations

Different pH

Different transit times

18

How does the number of microbial cells compare to human cells?

There are more microbial cells

19

How much bacteria is there in the human gut?

100 trillion

20

What are the different parts of taxonomy?

Life

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

21

Why must meaningful comparison between bacteria be done at the genus level?

Bacterial comparison at the phylum level is a higher level than grouping all mammals together

22

What impact does diet have on bacteria?

Impacts diversity

23

What does OTU stand for?

Operational taxonomic unit

24

What does a higher number of OTUs mean?

Higher diversity

25

How are the vast majority of bacteria in the GI tract beneficial for health?

Different bacteria perform different functions

Bacteria act together in a population

Bacteria communicate with each other and with the host

A diverse microbiota is important to maintain health

26

What are some functions of gut microbiota?

Modifications of host secretions (mucin, bile, gut receptors etc)

Defence against pathogens

Metabolism of dietary components

Production of essential metabolites to maintain health

Development of the immune system

Host signalling

27

How does the gut microbiota provide defence against pathogens?

Competition

Barrier function

pH inhibition

28

What host secretions do the gut microbiota modify?

Mucin

Bile

Gut receptors

29

Why is junk food bad although it contains lots of energy (calories)?

Does not feed out gut microbes, that grow on fibres

30

What kinds of food is fibre found in?

Fruit

Vegetables

Pulses

Whole grains