GI System Flashcards
What is the digestive system composed of?
GI tract
Accessory Digestive organs
How is the GI tract protected from pathogen colonization?
Chemical, mechanical and cellular defences in place
Where in our body can you find gut bacteria?
Large Intestine
Small Intestine
Mouth
Stomach
What kind of microflora is most common in the mouth and what does it produce?
Bacteria is the most common
-some cause acid which leads to tooth cavities, tartar and calculus on teeth
Why is the esophagus and stomach largely free of microbes?
Because of its highly acidic environment (heart burn for esophagus)
-although some bacteria do survive the stomach
What bacteria survives in the stomach?
Hylicobacter pylori
- causes stomach ulcers
- Produced a compound around itself so it can survive in the acid
On the phylogenetic tree where is hylicobacter pylori?
Epsilon in the proteobacteria
Where are most microbes found in the body?
large intestines has the most species and numbers of bacteria
Which bacterium dominate fecal matter?
Bacteroides and E coli
How long does food stay in the large intestine and how does that relate to bacteria?
A long time so the bacteria have a longer time for microbial metabolic action and reproduction
What do bacteria in the large intestine produce?
Gas, acids and materials we can use such as vitamin K
Where on the phylogenictree would you find E. coli and bacteroides?
Both are gamma and apart of proteobacteria
What is dental plaque?
Coating of tooth enamel composed of polysaccharide slime materials excreted by bacteria
- mainly from streptococcus mutans
- moimized by brushing teeth and flossing
Why is dental plaque bad?
Complex bacterial communities build up and lives in the plaque, making acid as a by-product which attacks tooth enamel, leading to cavities
Why are cavities bad?
- Cosmetic problem, allows for improper processing of food
- May be an entry point for bacteria into the blood
What does dental plaque also cause?
Plaque will build up below th gum line and cause gum inflammation (gingivitis)
What is periodontitis?
Caused by gingivitis where tooth loss and bone damage in the mouth occurs
What does the term food poisoning mean?
Situations in which there is bacterial contamination of food and those bacteria grow IN the food and release toxins INTO the food which will exert their effects on the person who eats the food
-is an intoxication, NOT an infection
What does the term food borne infection mean?
Bacteria which re present in food and water which are taken into the digestive tract and which survive and grow
May be that once the bacteria are in the digestive tract that they will also produce toxins as with food poisoning situations, but the clear distinguishing feature is that in this case it is survival and growth of ingested bacteria in the digestive tract that allows disease
In terms of food poisoning, what are ways to destroy the toxin?
Heating the food prior to serving so the toxin is destroyed along with the bacteria the produced it
Does heating always work in killing toxins?
No, heating could kill bacteria that made the toxins but the toxin could NOT be destroyed. So once food is ingested it will still be poisonous
What is the key point in food poisoning?
It is bacteria that can grow in the food before it is eaten that is the problem.
-they produce toxins and it is the toxins that cause damage in the person, NOT DIRECTLY the bacterium that released the toxins
What is the major problem in food borne infections?
Bacteria contaminate the food and then those bacteria are transferred to the digestive tract when a person eats
-once bacteria are int he digestive tract disease begins
What are the 2 ways in which food borne infection agents cause damage?
- bacteria can grow in numbers and release toxins
2. Bacteria are invasive and to some degree cross the lining of the digestive tract or lodge in it to cause damage
How do you get rid of food more infections?
Usually heating the food prior to consumption kills the bacteria and there is no longer danger.
-may taste “off” so it contains no toxin and is safe to eat only IF the heating killed ALL bacteria
How do you avoid bacteria growth on food?
Once food is cooked cover it, then:
- Keep it got enough so no bacteria can live or reproduce
- Cool it fast to reduce bacteria reproduction