Microbiota of GI Tract

Question 1

why are more bacteria typically found the further down the GI tract you go

Answer 1

cause longer transit times yo :)

Question 2

describe the oxygen availability as you go down the GI tract

Answer 2

increasingly anaerobic conditions

Question 3

probiotics

Answer 3

live bacteria

Question 4

where can anaerobic bacteria exist

Answer 4

grow in the presence of oxygen and absence of oxygen

Question 5

where can obligate anaerobes grow

Answer 5

cannot grow in presence of oxygen

Question 6

pH mouth

Answer 6

6.5-7.5

Question 7

pH stomach

Answer 7

1.5-4

Question 8

pH duodenum

Answer 8

7-8.5

Question 9

pH colon

Answer 9

5.5-6.5

Question 10

pH small intestine - duodenum

Answer 10

4 -> 7

Question 11

explain the usefulness of knowing phyla of bacteria

Answer 11

less useful than knowing something is a mammal; could be an elephant, vole, platypus and ya wouldnae know

Question 12

what level do meaningful comparisons of bacteria have to take place at

Answer 12

genus level

Question 13

what do GIT microbiota do? their function etc.

Answer 13

metabolism of dietary components

production of essential metabolites

modification of host secretions

defence against pathogens (competition etc.)

development of immune system

Question 14

what type of food doesn’t provide any energy to our gut microbes

Answer 14

junk food

Question 15

what do GIT microbes like to grow on

Answer 15

grow on fibre

energy absorb ed in large intestine

Question 16

what percentage of energy is absorbed in stomach/ small intestine

Answer 16

70%

Question 17

what percentage of food is absorbed in the large intestine

Answer 17

5-10%

Question 18

health protection benefits of including fibre in our diet

Answer 18

improves faecal bulking, improving passage resulting in shorter transit time

contains important chemicals, vitamins etc/

feeds our bacteria

Question 19

results of bacterial fermentation

Answer 19

• releases additional phytochemical

maintains slightly acidic pH

increased commensal bacteria population and pH improves resistance to pathogens

essential supply of short chain fatty acids

Question 20

effect of branched short chain fatty acids on your health

Answer 20

have a negative impact

Question 21

how to gut microbiota provide defence against pathogens

Answer 21

1. barrier effect (large numbers of host bacteria prevent colonisation by ingested pathogens)
2. active competitive exclusion

Question 22

what is optimum growing pH for pathogens

Answer 22

> 6

Question 23

why don’t pathogens tend to be present in proximal colon

Answer 23

pH too low