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Flashcards in Immunology Deck (42)
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1

What are the key features of the Immune System?

- Able to specifically identify non-self and danger signals.
- Able to modify the response to deal with different pathogens.
- Able to actively promote tissue repair and healing.
- Able to remember any pathogen it encounters. (Immunological Memory)

2

Name some constitutive barriers to infection?

- Skin.
- Mucous.
- Commensal Bacteria.

3

Describe the skin barrier.

- Physical barrier: multi-layered, renewal and replacement.
- Physiological factors: low pH 5.5, low O2 tension.
- Sebaceous glands: secrete hydrophobic oils, lysozyme, ammonia, antimicrobial peptides.

4

Describe the mucous barrier.

- Mucous membranes: Secrete mucous where cavities come into contact with the environment.
- Physical barrier: traps invading barriers.
- Secretory IgA: prevents Bac and Virus attaching and penetrating epithelial cells.
- Contains enzymes: lysozymes, defensins and antimicrobial peptides directly kill. Lactoferrin starve bacteria of iron.
- Cillia trap and physically remove pathogens.

5

Describe the commensal bacteria.

- 100 trillion (10^14) normally reside at epithelial surfaces.
- Produce Bactercidins influencing other bacteria.
- Reduction in pH of large bowel.
- Competition for essential nutrients,
- Production of anti-microbial short-chain fatty acids.
- Synthesis of vitamins K and B12.

6

How important are commensal bacteria?

- Eradication of normal flora with broad-spectrum antibiotics commonly result in infection.
- Organisms rapidly colonize an undefended ecological niche.

7

How are constitutive barriers breached during health care?

- Insertion of intravenous lines, catheters, nasogastric tubes.
- Antibiotics.
- Anti-acids, nasal decongestants, anti-bacterial wipes.

8

Name the Major Components of the immune system.

- Cells: Leukocytes, White blood cells.
- Soluble factors: Humoral factors.

9

Name Phagocytes.

- Neutrophils.
- Monocytes and macrophages.
- Dendritic cells.

10

Name Lymphocytes.

- T cells.
- B cells.
- Natural killer cells.

11

Name other cells.

Mast cells, Eosinophils and Basophils.

12

Name Humoral factors.

- Antibodies.
- Complement system proteins.
- Cytokines.
- Acute phase proteins.

13

Cytokines.

- Diverse collection of small proteins and peptides produced in response to infection, inflammation and damage.
- Modulate behaviour of cells so play a key role in coordinating the immune system.
- Multiples overlapping functions.
- Short half-life.
- Local or systemic.

14

Antibodies.

- Protein produced in response to specific antigen.
- Produced by antigen-activated B Cells.
- Defend against pathogens, viruses and toxins.

15

T cells and B cells.

- Mature cells circulate through the blood, lymph, and secondary lymphoid tissues.
- Inactive until meet pathogen/antigen.
- Some are very long lived. (memory T and B).

16

B Lymphocytes.

- Responsible for production and secretion of antibodies to defend against pathogens.

17

T Lymphocytes.

- Helper T cells: Key regulators of immune system.
- Cytotoxic T cells: Kill virally infected body cells.

18

Natural Killer cells.

- Large granular lymphocytes.
- Can detect and kill tumour cells and virally infected cells.
- Can kill antibody-bound cells/pathogens.

19

Mast cells.

- Reside in tissues and protect mucosal surfaces.

20

Basophils, Eosinophils.

- Circulate in blood.
- Recruited to sites of infection by inflammatory signals.

21

Mast, Basophils and Eosinophils.

- Highly granular.
- Release Histamine, Heparin, and pro-inflammatory cytokines.
- Defense against pathogens that cannot be phagocytosed. (worms)
- Key role in mediating allergic responses.

22

Complement system.

- Approx. 30 proteins.
- Produced in Liver.
- Circulate in blood as inactive precursors.
- Enter infected/inflamed tissues.
- Enzymatically cleave and activate more in biological cascade.

23

Monocytes, Macrophages, and Neutrophils.

- Phagocytes.
- Ingest and clear debris from body.
- Important source of Cytokines.

24

Monocytes.

- Circulate in the blood.
- Migrate to peripheral tissues and differentiate into macrophages.

25

Macrophages.

- Long-lived tissue resident in phagocytes.
- Kupffer = Liver.
- Alveolar = Lung.
- Mesangial = Kidney.
- Microglial = Nervous.
- Limit inflammation, tissue repair, antigen presentation.

26

Neutrophils.

- Phagocytic cells that circulate in the blood.
Rapidly recruited into inflamed, damaged, and infected tissues.

27

Dendritic cells.

- Present in peripheral tissues in an immature state.
- Phagocytose antigens.
- Mature and migrate into secondary lymphoid tissues where they play a key role in antigen presentation.

28

Comparing dendritic, macrophage, and neutrophils.

- Neutrophils: Complete destruction of proteins are seen.
- Dendritic: Partially degraded for antigen presentation and stimulation of adaptive response.
- Macrophages: Neutral = Clearance of dead host cells.
Activated = phagocytosis of pathogens.
Repair = reduced activity, produce pro-inflammatory cytokines.

29

Primary Lymphoid Tissues.

- Sites of Leukocyte development.

30

Where do Lymphocytes mature and circulate?

- Mature: bone marrow or thymus.
- Circulate: between blood, secondary peripheral lymphoid tissues and lymph.