Introduction to the Microbiology of the Gut Flashcards
What makes up our gut flora?
It is a combination of all the bacteria interacting with each other that creates a healthy environment for them to grow, and a healthy gut for us.
What are some host defences that protect us from all these organisms in our guts?
STRUCTURAL:
- seamless epithelium
- tight junctions
- sloughing/turnover
MECHANICAL:
- peristalsis
- chewing
- fluid movement
BIOCHEMICAL:
- gastric acid
- bile
- mucous
IMMUNOLOGICAL:
- secretory IgA
- intra-epithelial lymphocytes
What are some benefits of gut flora?
1) colonisation resistance
2) metabolites of benefit to the host
3) normal development of immunity (tolerance, etc.)
4) aids digestion
What is gastroenteritis?
It is an acute syndrome characterisation by gastrointestinal symptoms in any combination, including:
- nausea
- vomiting
- diarrhoea
- abdominal discomfort thought to be caused by an infection
What is diarrhoea?
The frequent passage of loose, fluid, unformed stools.
It is defined as watery or liquid stools, and an increase in daily stool frequency and often a sense of urgency.
What is dysentery?
It is an inflammatory disorder of the GI tract - usually in the large intestine.
It is often associated with blood and pus, pain, fever, abdominal cramps.
What is enterocolitis?
It is inflammation involving the mucosa of the small and large intestine.
What is some damage resulting from infection of the gastrointestinal tract?
1) pharmacological action of bacterial toxins
2) local inflammation in response to a superficial microbial invasion
3) deep invasion to blood and lymphatics and dissemination of the organism to other body sites
4) perforation/ulceration of mucosal epithelium
What are some mechanisms of bacteria/viruses/etc. that cause diarrhoea?
- bacterial toxins (affect fluid/electrolyte transport) [eg. cholera]
- adherence (causes damage to the epithelium) [eg. E.coli]
- penetration and invasion
