IAH 2 - Physical, microbiological and chemical barriers to infection Flashcards
What are the main functions of the immune system?
- Recognition of non-self-microbes & viruses
- Effector function (contain/eradicate infection)
- Regulation (appropriate and measured response) - prevent inappropriate immune responses such as chronic inflammation or hypersensitivity
- Memory - immediate and stronger response on second exposure
What are the 2 types of immunity?
Innate and adaptive
What is the response of innate immunity?
Fast Fixed - intensity always similar Limited number of specificities Constant during response Activates and reinforces adaptive response
What is the response of adaptive immunity?
Slow
Variable response due to antigen specificity
Numerous highly selective specificities
What immediate effect mechanisms are there?
Physical, chemical and microbiological barriers
Complement
Phagocytosis
What induced effect mechanisms are there?
Cytokines and chemotaxis Interferon response Antibodies Cell-mediated immunity Memory
What induces chemotaxis and the interferon response?
Cytokines
What is the physical barrier to infection in the skin and what layer is it found?
Keratin
Present in the stratum lucidum
What can allow for opportunistic infections to enter through the skin?
Burn-moist surface, vascular damage
Cuts/surgery
Acne
Where is the bacteria present in the skin, that causes acne?
Infected sebaceous gland ducts or hair follicles
What is mucin?
Highly glycosylated protein
What components is mucous made up of?
Mucin and water
Where is mucin secreted?
Goblet cells
What cells is mucous trapped in the airways?
And what destroys these cells?
Ciliated epithelium
Smoking or cystic fibrosis
What mucosal surfaces are physical and chemical barriers to infection?
Internal body surfaces (mucosal surfaces)
Saliva
GI tract
How do internal body surfaces (mucosal surfaces) work as a barrier to infection?
- Large surface area
- No keratin
- Mucins: coat microorganisms preventing attachment
- Ciliated epithelium (protection and ejection of large particles)
- Flow of air and fluid
What 2 enzymes do saliva contain to fight infection? And what are their functions?
Lysozyme - digests bacterial cell walls
Lactoferrin - removes iron required by bacteria
How does the GIT work as a barrier to infection?
- Acid environment in stomach, bladder, kidney, bile
* Digestive enzymes inhibit growth
What infections can develop with abnormally thick mucus
Lung infections e.g. P.aeruginosa infection
What exposure can lead to corneal and ear infections?
Water exposure
Why can there be higher rate of sepsis after surgery in e.g.colon?
As it is an area of high flora