Innate Immunity (Non-Specific)

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  • Created by: Izzy2807
  • Created on: 28-11-19 17:30
What is a pathogen?
A disease-causing microorganism (bacteria, virus, fungus)
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What are the 4 types of barriers for infection?
Physical- Skin & Mucus Membranes. Mechanical: Expulsion responses or Mucocilary Escalator. Chemical: Antimicrobial chemicals and proteins found in blood or other body fluids. Cellular: Leukocytes!
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How does a leukocyte detect a pathogen?
All pathogens have specific proteins, carbohydrates and lipids. The AA sequence of the proteins will fit an immune cell receptor.
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How does the skin protect us from pathogens?
Physically tough (kerratin) barrier between internal and external environment. Waterproof, oily and abrasion resistant. Acidic and dry so not suitable for pathogens. Flora on epidermis and phagosomes on dermis.
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How do mucus membranes protect us from pathogens?
Mucus traps microbes and contains enzymes that break down the cell walls of microbes, has phagosomes and antimicrobial peptides.
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What is the mucocilary escalator? (mechanical barrier)
Cilia on the epithelial cells of the alveoli waft (move) the mucus up and out of the lungs, so the mucus can be coughed out.
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What are the mechanical expulsion movements?
Coughing, sneezing, spitting vomiting, excretion of faeces (peristalsis) and tears
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What are lysozymes? (Chemical barrier)
Enzyme found in saliva, sweat and tears that destroys the cell walls of some bacteria
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What is transferrin? (Chemical barrier)
A protein that binds to iron which limits bacterial growth (iron not accessible to bacteria)
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What is interferon? (Chemical barrier)
A protein that limits viral replication in neighboring cells and activate Natural Killer cells and Macrophages
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What is a complement protein/chemical? (CB)
Enhancing inflammation – they trigger histamine release. Opsonisation. Cytolysis - rupture of cell membrane via membrane attack complex (MAC).
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How does a interleukin 1 enzymatic protein destroy a pathogen?
Induce a fever and produce opsinising acute phase proteins
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What are the two main cellular responses?
Phagocytosis and degranulation (& release of inflammatory factors)
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How does infection cause tissue damage?
Often due to the release of enzymes, using up nutrients, changing the DNA integrity (e.g. reverse transcriptase)
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Describe phagocytosis!
Phagocyte detects pathogen due to chemicals. Pathogen binds to phagocyte receptors, membrane forms around pathogen and it is engulfed. Pathogen now in membrane (phagosome), fuses with lysosome and lysozymes break down pathogen contents.
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What is degranulation and the release of inflammatory mediators?
When granules (containing cytotoxins and antimicrobial toxins) are released outside of a cell. Inflammatory mediators are histamines and Bradykinin (released by mast cells) cause inflammatory response.
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What is the main purpose of the inflammatory response?
Coagulation of blood, remove debris and restore/promote tissue healing
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What does the release of histamines and Bradykinin cause?
Vasodilation (more immune cells to site) which also results increased vascular permeability for same reason
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What are the reasons behind the 4 cardinal signs of inflammation? Pain, Heat, Swelling and Redness
Pain: histamine stimulates the nerve endings. Swelling: increase in vascular permeability, plasma and fluid leaks outside of BVs into tissue. Redness: vasodil. Heat: vasodil, more heat carried in blood
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What are chemotactic factors, released by WBCs?
Proteins that signal immune cells that there is a pathogen in a specific locomote, cause chemotaxis
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What are the 4 killing cells?
Killer T cells (granular lymphocytes or perforins), eosinophils (extracellular killing), basophils/mast cells, phagocytes (neutrophils/macrophages)
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What are the main killing techniques in innate immunity?
Complement (inflammation and enzyme activity), lysis (cell destruction), interferon protein response, pre-radical production (oxidization)
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What cells produce histamines?
Basophils and mast cells
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What are dendritic cells?
Antigen presenting cells for T-Cell recognition
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What are cytokines?
Chemical signal molecules
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What are perforin proteins and granzymes?
Proteins that perforate and destroy microbes
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What are lymphocytes and where are they formed?
Immune cells specific to the lymphatic system (circulation of lymph fluid). Bone marrow produces B-cells, Thymus produces T-Cells. The spleen has some lymphocytes and macrophages.
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Other cards in this set

Card 2

Front

What are the 4 types of barriers for infection?

Back

Physical- Skin & Mucus Membranes. Mechanical: Expulsion responses or Mucocilary Escalator. Chemical: Antimicrobial chemicals and proteins found in blood or other body fluids. Cellular: Leukocytes!

Card 3

Front

How does a leukocyte detect a pathogen?

Back

Preview of the front of card 3

Card 4

Front

How does the skin protect us from pathogens?

Back

Preview of the front of card 4

Card 5

Front

How do mucus membranes protect us from pathogens?

Back

Preview of the front of card 5
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