Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Alimentary System > The Microbiota of the GI Tract 1 > Flashcards

The Microbiota of the GI Tract 1 Flashcards

1
Q

What is the transit time in the mouth?

A

1 minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the transit time in the oesophagus?

A

4-8 seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the transit time in the stomach?

A

2-4 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the transit time in the small intestine?

A

3-5 hours

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the transit time in the colon?

A

10 hours to several days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does transit time affect?

A

Bacterial populations due to different bacterial growth rates

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

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

A

Increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does anaerobic mean?

A

Living in the absence of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does aerobic mean?

A

Living in the presence of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are different classes of anaerobic bacteria?

A

Facultative anaerobic bacteria

Obligate anaerobic bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are facultative anaerobic bacteria?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are obligate anaerobes?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are examples of bacteria found in the stomach?

A

Lactobacillus

Candia

Streptococcus

Helicobacter pylori

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are examples of bacteria found in the colon?

A

Bacteroides

Clostridium

Bifidpbacterium

Enterobacteriaceae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What class of anaerobes are found in the stomach?

A

Faciltative anaerobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What class of anaerobes is found in the colon?

A

Obligate anaerobes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

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

A

Different oxygen concentrations

Different pH

Different transit times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

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

A

There are more microbial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How much bacteria is there in the human gut?

A

100 trillion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the different parts of taxonomy?

A

Life

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

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

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What impact does diet have on bacteria?

A

Impacts diversity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does OTU stand for?

A

Operational taxonomic unit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does a higher number of OTUs mean?

A

Higher diversity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

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

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are some functions of gut microbiota?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How does the gut microbiota provide defence against pathogens?

A

Competition

Barrier function

pH inhibition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What host secretions do the gut microbiota modify?

A

Mucin

Bile

Gut receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

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

A

Does not feed out gut microbes, that grow on fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What kinds of food is fibre found in?

A

Fruit

Vegetables

Pulses

Whole grains

31
Q

Where are the products created by bacteria that are derived from fibres absorbed?

A

Large intestine

32
Q

As well as fibre, what else can GIT microbes use for growth?

A

Endogenous (host-derived) substrates

33
Q

What are benefits of including dietary fibre in our diet?

A

Improves faecal bulking, eases passage, results in a shorter transit time

Contains important phytochemicals, anti-oxidants and vitamins

Bacterial fermentation

34
Q

How does bacterial fermentation impact pH?

A

Maintains slightly acidic pH

35
Q

What are the benefits of bacterial fermentation?

A

Releases additional phytochemicals

Maintains slightly acidic pH that improves resistance to pathogens

Essential supply of short chain fatty acids

36
Q

What are the 3 main fatty acids provided by bacterial fermentation?

A

Butyrate

Propionate

Acetate

(1:1:1 ratio)

37
Q

What are the functions of butyrate?

A

Epithelial cell growth and regeneration

38
Q

What are the functions of propionate?

A

Gluconeogenesis in the liver

Satiety signalling

39
Q

What are the functions of acetate?

A

Transported in the blood to peripheral tissues

Lipogenesis

40
Q

How does the colon change in regards to bacterial fermentation?

A

Proximal is carbohydrate rich, pH midly acidic and transover rapid

Distal has little fermentable carbohydrates, pH neutral and turnover slow

41
Q

How does bile acid concentration change along the bowel?

A

Increases going proximal to distal

42
Q

How much carbohydrates are metabolised by bacteria per day?

A

About 40g/day

43
Q

How much protein is metabolised by bacteria per day?

A

12-18g/day

44
Q

What are important gut microbial activities driven by?

A

What we eat

45
Q

What are the functional importance of firmicutes?

A

Butyrate production

Polysaccharide utlisation

Propionate production

46
Q

What is the functional importance of aminomycetes?

A

Utilise prebiotics

Lactate production

47
Q

What is an example of an actinomycete?

A

Bifidobacteria

48
Q

How does the GI microbiota provide have a barrier effect for defence?

A

Large number of the indigenous microbiota prevent colonisation by ingesting pathogens and inhibit overgrowth of potentially pathogenic bacteria normally resident at low levels

49
Q

How does the GI microbiota provide active competitive exclusion for defence?

A

Conferred by both microbe-microbe and microbe-host interactions

50
Q

How does the GI microbiota protect against pathogens due to pH inhibitions?

A

Generally pathogens grow opimally at pHs over 7

51
Q

Is the pH greater in the proximal or distal colon?

A

Distal

52
Q

What forms a barrier between the luminal bacterial population and the epithelial cells to keep the gut health?

A

Mucus layer

53
Q

What are the different layers of bacteria after the mucus layer?

A

Inner layer and outer layer

54
Q

What happens when the mucus bacterial of the colon disrupted?

A

Bacterial cells penetrate the mucus layer and the epithelial barrier

55
Q

What is the largest lymphoid organ in the body?

A

Gut

56
Q

What must be gut be able to do due to being in constant interaction with the environment?

A

Respond appropriately to foreign/pathogenic agents

Actively down-regulate immune responses to “self” proteins, dietary antigens and the commensal microbiota

Recognise and respond to pathogenic invasions

57
Q

Why do autoimmune diseases occur in relation to the gut?

A

Immune system can no longer distinguish between harmful pathogens and commensal bacteria

58
Q

What does imbalance between the gut microbiota composition lead to?

A

Disrupting homeostasis causing inflammation

59
Q

What are the 2 possible effects that gut bacteria can have on inflammation?

A

Some are pro-inflammatory and some are anti-inflammatory

60
Q

What are important signalling molecules that gut microbiota produce?

A

Short chain fatty acids

61
Q

What impact do short chain fatty acids from bacteria have on the gut epithelial cells?

A

Secretes gut hormones

62
Q

What receptors on the gut epithelium detects short chain fatty acids from bacteria?

A

GRP43/FFAR2

GPR/FFAR3

GPR109A

63
Q

What does SCFA stand for?

A

Short chain fatty acid

64
Q

What are GPR43/FFAR2 receptors activated by?

A

Acetate

Propionate > butyrate

65
Q

What does activation of GPR43/FFAR2 receptors cause?

A

GLP-1 secretions (inhibits fat accumulation)

66
Q

What does GLP-1 do?

A

Inhibits fat secretions

67
Q

What does activation of GPR/FFAR3 receptors do?

A

Results in PYY secretion (improves insulin resistance and satiety signalling to brain)

68
Q

What activates GPR/FFAR3 receptors?

A

Propionate and butyrate

69
Q

What does PYY do?

A

Improves insulin resistance and satiety signalling to brain

70
Q

What activates GPR109A receptors?

A

Butyrate

71
Q

What does activation of GPR109A receptors cause?

A

Suppreses colonic inflammation and carcinomogenesis (anti-inflammatory cytokines such as IL-10)

72
Q

What happens to microbial metabolites that are not utilised by gut epithelial cells?

A

Absorbed into the bloodstream and transported around the body

73
Q

What can be said about microbial composition throughout life?

A

It changes throughout life

74
Q

What are some different factors that influence the microbiota throughout life?

A

Anatomy is the same, food is different

Dietary changes cause the greatest influence

Our food is out microbiotas food

Alimentary System (41 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions