Roopchand lecture 1 Flashcards
How is the gut microbiota organized?
The gut organs are organized so that as you move deeper into the gut you will notice that the amount of microbes increase.
Different types of bacteria in the gut
-Bacteriodetes and firmichutes make up 90% of gut bacteria.
- 10^12 g of bacteria/feces
- archea
- viruses
- fungi
- protozoa
- helminths
What do bacteria in the gut microbiota do to contribute to host health
- Bacteria break down food to produce metabolites that contribute to host health
- release antimicrobial peptides to kill pathogens (bacteriocins)
- compete with pathogens for nutrients and cellular binding sites
- first line of defense against pathogens
What is -SA of GI -Villi -Microvilli -
- 20-30m^2
- villi-threadlike projections on the surface of membranes that cause increase surface area and make it easier for nutrients to be absorbed and for liquid to pass through
- microvilli- are enterocytes with fingerlike projections on top of them
Mucins -what are they -made of Location -stomach -small intestine
-made of glycoproteins covering intestinal, stomach and colon linings
-made of >80% polysaccharide
Located on stomach and colon:
-double layer to protect from acid and microbes
Located on intestine:
-covers outside to maximize nutrient absorption
-release antimicrobials to kill pathogens
what is metabolic syndrome?
This a condition that increases the risk of cardiovasclular diesease and type 2 diabetes
what is metabolic syndrome?
This a condition that increases the risk of cardiovasclular diesease and type 2 diabetes and can be caused by
- genetic predisposition
- diet and physical activity
- low physical activity and high calorie intake
Why do insulin resistant cells absorb glucose properly
This is because when intestinal inflammation occurs and bacteria break through the intestinal barrier insulin receptors are phosporolated which causes a decrease in their functioning. Because of this they stop being able to take in glucose causing it to build up in the blood stream
What are the LG5+ stem cells?
The are stem cells located in the crevices of intestines which diffrentiate into the various types of cells that make up the intestine.
What are the intestinal cells:
- paneth- -Colonocytes:
- m cells -Goblet cells
- goblet cells
- tuft cells
- endocrine
Paneth- secrete specific amps and mucins (antimicrobial peptides and are unique to the SI
M cells: sample molecules to see if they are antigens and then send them to immune cells
goblet cells- produce mucins and are located in the small intestine and the gut
tuft cells-chemosensory cells which defend against helminths
Endocrine cells-secrete hormones and are located in the small intestine and colon
-colonocytes-reabsorb electrolytes and water
- Time line of gut microbiota development:
- env. factors that shape it after 2-5 years
- In fetus:placenta protects fetus from microbes
- Before 2-5 years: vaginal birth vs. c-section and breast feeding vs. bottle feeding
- colonizes/stabailizes after 2-5 years and is then shaped by:
- environment
- age
- health
- urban or rural
- stress
How does prediabetes progress to type 2 diabetes?
Prediabetes begins by insulin receptors losing their responsiveness to glucose and as a result the body will start manufacturing more insulin to make up for this. the body beta pancreas cells will eventually get tired of producing insulin and the amount of post meal glucose will end up build up in the body.
Changes in food supply in the global map?
Western countries like the UK, US, Australia and New Zealand have increased in the amount of calorie dense foods that they are consuming
Healthy diet vs. WD
Healthy diet: Low levels of firmichutes to bacterichetes ratio and normal levels of inflammation
Western diet: Dysbiosis, or high levels of firmichutes to bacteriochetes ratio. Tight junctions are weak and they break and LPS gets in causing inflammation
Mouse experiment: two germ free mice were given feces from lean twin and feces from fat twin.
lean feces»>lean mouse
Fat feces»>fat mouse
LPS and and endotoxemia
LPS is carried by the chylomicrons which is produced in the intestine and carried out through the circulation in the where it can break into the intestinal barrier and bind to immune cells activating their toll receptor causing inflammation to occur.
