Immune System Flashcards
What is the immune system?
A complex system responsible for distinguishing host cells from foreign material - in order to protect against infections.
What structures enable the immune system to recognise something as foreign?
1) MAMP (microbe-associated molecular patterns)
2) Antigens
The 7 stages of the infectious disease process?
1) Transmission or spread of bacteria
2) Entry into a body and colonisation - infection
3) Obtains the essential nutrients for growth
4) Avoids the host’s defence mechanisms (innate and adaptive)
5) Spreads within the host or to other hosts
6) Effects the host
7) Host response
What are the 2 types of the immune system’s defence mechanisms?
1) Innate
2) Adaptive
What are the 3 differences between the innate and adaptive defence mechanisms?
1) Innate mechanisms target a broad range of pathogens whereby adaptive mechanisms target specific pathogens.
2) Innate mechanisms are rapid (minutes, hours) whereas adaptive mechanisms take longer (days)
3) Innate mechanisms do not develop memory whereas adaptive mechanisms do develop memory
What are the 9 immune tissues called?
1) Blood
2) Tonsils and adenoids
3) Lymph nodes (in the neck, armpits and groin)
4) Lympathic vessels
5) Thymus
6) Spleen
7) Peyer’s patches (small intestine)
8) Appendix
9) Bone marrow
4 components of innate immunity?
1) Barriers = a) Physical & b) Chemical barriers
2) Antimicrobial agents
3) Specialised cells = a) Natural Killer cells & b) Phagocytes
4) Inflammation & Fever
What are the 5 physical barriers?
1) Skin
2) Eyes
3) Respiratory Tract
4) Gastrointestinal Tract
5) Genitourinary Tract
What 5 things makes the skin a physical barrier?
1) Sweat
2) Antimicrobials
3) Low pH
4) Commensal bacteria
5) Shedding of the skin
What makes the eyes a physical barrier?
Tears (contain lysozyme)
What 2 things make the respiratory tract a physical barrier?
1) Mucus
2) Ciliated epithelium
What 5 things make the gastrointestinal tract a physical barrier?
1) Stomach acid
2) pH change in the duodenum
3) Normal flora
4) Mechanical removal (vommiting)
5) Lysozyme
What 4 things make the genitourinary tract a physical barrier?
1) Passing of urine
2) Urine acidity
3) Vaginal secretions
4) Lysozyme
What do the chemical barriers involve:
Cell-signalling molecule = cytokines (e.g. interferons)
How do cytokines (e.g. interferons) provide an immune response?
They will carry out an immune response against viruses.
1) A cell is infected with a virus
2) The infected cell produces and secretes interferons
3) The interferons will bind to the receptors on nearby cells
4) This triggers the anti-viral response inside the infected cell
5) Infected cell is left undamaged
What are the 2 types of natural killing cells?
1) White blood cells
2) Tissue-dwelling cells
What do the natural killing cells do?
1) Recognise INFECTED cells
2) Kill the infected cell
3) The natural-killing are left undamaged.
What 2 types of cells can carry out phagocytosis?
1) White blood cells
2) Tissue dwelling cells
What occurs in the process of phagocytosis?
1) The microbe attachers to the phagocyte (via a non-specific receptor)
2) A phagosome forms around the microbe.
3) The microbe will fuse with the lysosome in the phagosome.
4) The digestive enzymes are released from the lysosome.
5) The microbe is digested and microbial agents are released from the phagocyte.
What other cells are involved in innate immunity and why?
Polymorphonuclear cells (basophils, neutrophils eosinophils)
1) The first to arrive at the site of infection
2) They contain granules - that allow them to chemically attach microbes.
When does inflammation occur?
Inflammation will occur when a cell experiences traumas (e.g pathogenic invasion)
Local inflammatory response
Is important to clear an infection
Widespread systemic response
Can cause septic shock and death (especially in bacterial infections)
What are the 7 basic stages of inflammation?
1) Tissue is damaged and released inflammatory mediators (aka: cell-signalling molecules).
2) Inflammation occurs
3) The permability of the endothelium increases.
4) Blood accumulation
5) Clotting factors (plasma proteins) leak out of the endothelium
6) Blood clot forms
7) CHEMOTAXIS of white blood cells (neutrophils & macrophages)
8) Initiation of tissue repair.