Lecture 14

Question 1

gut microbiome represents the…

Answer 1

greatest density/diversity of microbes in the body

Question 2

roughly half of faeces produced is

Answer 2

microbes

Question 3

probiotics=

Answer 3

live microorganisms that confer a health benefit on the host

Question 4

2 examples of probiotics

Answer 4

Bifidobacterium and Lactobacillus

Question 5

prebiotics=

Answer 5

selectively fermented ingredient that results in specific changes in the composition and/or activity of the GI microbiota

Question 6

example of a pathobiont

Answer 6

C. difficile

Question 7

intestines contain more _ than any other organ

Answer 7

immune cells

Question 8

in GI tract; single layer of cells separates the _ from the _

Answer 8

luminal contents from the host

Question 9

4 layers of the gut wall:

Answer 9

• mucosa
• submucosa
• muscularis
• serosa

Question 10

the inner most layer of gut wall=

Answer 10

mucosa- single layer of columnar epithelium

Question 11

mucosa has _ which increases the SA

Answer 11

villi

Question 12

what layer of the wall is connective tissue

Answer 12

submucosa

Question 13

what layer of the gut wall is thick muscle

Answer 13

muscularis- 2 layers: circular and longitudinal

Question 14

which layer of the gut wall secretes lubricating fluids

Answer 14

serosa

Question 15

villi in the small intestine increase _ and _ capacity

Answer 15

absorptive and digestive capacity

Question 16

epithelial cells can emerge from _ within _ and migrate up towards surface

Answer 16

stem cells
within crypts

Question 17

Paneth cells secrete

Answer 17

antimicrobial peptides

Question 18

more goblet cells and less epithelial cells as you move down the GI tract=

Answer 18

deeper mucous barrier ‘glycocalyx’

Question 19

the highest level of SCFAs are found in the

Answer 19

proximal colon- used locally by enterocytes or transported across gut epithelium into bloodstream

Question 20

2 major SCFA signalling mechanisms=

Answer 20

• inhibition of histone deacetylases
• activation of G-protein coupled receptors

Question 21

buffered stool example:

Answer 21

OMNI gene gut- very commonly used
- stable at room temp >60 days
- cannot be used for functional assay later

Question 22

stool may not be reflective of…

Answer 22

mucosa-associated microbes and proximal luminal contents

Question 23

in brush sampling you…

Answer 23

pass sampling device into rectum and brush mucosal wall
- invasive/expensive

Question 24

fermentation of fibre supports the growth of microbes that produce…

Answer 24

the metabolites SCFAs

Question 25

higher SCFAs correlate with

Answer 25

lower obesity

Question 26

what SCFA is the main energy source for epithelium

Answer 26

butyrate

Question 27

butyrate allows colonocytes to…

Answer 27

consume oxygen via B-oxidations maintain aerobic/anaerobic barrier

Question 28

propionate allows the regulation of…

Answer 28

gluconeogenesis and satiety (how we feel full)

Question 29

acetate is the essential metabolite for…

Answer 29

growth of other bacteria/cholesterol metabolism, lipogenesis, appetite regulation

Question 30

gut microbial enzymes contribute to

Answer 30

bile synthesis

Question 31

Akkermansia is negatively associated with

Answer 31

obesisty