Lecture 14 Flashcards
gut microbiome represents the…
greatest density/diversity of microbes in the body
roughly half of faeces produced is
microbes
probiotics=
live microorganisms that confer a health benefit on the host
2 examples of probiotics
Bifidobacterium and Lactobacillus
prebiotics=
selectively fermented ingredient that results in specific changes in the composition and/or activity of the GI microbiota
example of a pathobiont
C. difficile
intestines contain more _ than any other organ
immune cells
in GI tract; single layer of cells separates the _ from the _
luminal contents from the host
4 layers of the gut wall:
- mucosa
- submucosa
- muscularis
- serosa
the inner most layer of gut wall=
mucosa- single layer of columnar epithelium
mucosa has _ which increases the SA
villi
what layer of the wall is connective tissue
submucosa
what layer of the gut wall is thick muscle
muscularis- 2 layers: circular and longitudinal
which layer of the gut wall secretes lubricating fluids
serosa
villi in the small intestine increase _ and _ capacity
absorptive and digestive capacity
epithelial cells can emerge from _ within _ and migrate up towards surface
stem cells
within crypts
Paneth cells secrete
antimicrobial peptides
more goblet cells and less epithelial cells as you move down the GI tract=
deeper mucous barrier ‘glycocalyx’
the highest level of SCFAs are found in the
proximal colon- used locally by enterocytes or transported across gut epithelium into bloodstream
2 major SCFA signalling mechanisms=
- inhibition of histone deacetylases
- activation of G-protein coupled receptors
buffered stool example:
OMNI gene gut- very commonly used
- stable at room temp >60 days
- cannot be used for functional assay later
stool may not be reflective of…
mucosa-associated microbes and proximal luminal contents
in brush sampling you…
pass sampling device into rectum and brush mucosal wall
- invasive/expensive
fermentation of fibre supports the growth of microbes that produce…
the metabolites SCFAs
higher SCFAs correlate with
lower obesity
what SCFA is the main energy source for epithelium
butyrate
butyrate allows colonocytes to…
consume oxygen via B-oxidations maintain aerobic/anaerobic barrier
propionate allows the regulation of…
gluconeogenesis and satiety (how we feel full)
acetate is the essential metabolite for…
growth of other bacteria/cholesterol metabolism, lipogenesis, appetite regulation
gut microbial enzymes contribute to
bile synthesis
Akkermansia is negatively associated with
obesisty
