Topic 6B: Infection And The Non-Specific Immune Response Flashcards
What are the 4 major routes in which pathogens can enter body?
- Cuts in skin
- Digestive system (contaminated food)
- Respiratory system (Inhilation)
- Mucosal surfaces (Inside nose/mouth/genitals etc.)
What are the several barriers used to prevent infection of pathogens? (4)
– Stomach acid
– Skin
– Gut and skin flora
– Lysozymes
What are antigens?
Molecules (usually protein or polysaccharides) found on cell-surface
What activates and immune response?
Foreign antigens
What are the two types of immune response?
Specific and non-specific
Which immune response occurs first?
Non-specific then specific
What are the three mechanisms that are part of the non-specific immune response?
– Inflammation at the sight of infection
– Production of anti-viral proteins (Interferons)
– Phagocytosis and lysozyme action
What is inflammation?
And immune response by the sight of infection becomes red swollen and painful
Describe the steps in inflammation(5)
– Immune system cells recognise foreign antigens on surface of pathogen and release molecules that trigger inflammation
– Molecules cause vasodilation that increases bloodflow to site of infection
– Molecules also increase permeability of blood vessels
– Increased blood flow brings loads of immune system cells to site of infection and increased permeability allows cells to move out of the blood vessels and into infected tissue
–immune system cells start to destroy pathogens
What are anti-viral proteins called?
Interferons
How do interferons prevent viruses spreading to uninfected cells?(3)
– Prevent viral replication by limiting production of viral proteins
– Activate cells involved in specific immune response to kill infected cells
– Activate of the mechanisms of non-specific immune response such as promoting inflammation
Describe the events which occur when a macrophage/ phagocyte come into contact with a pathogen(5)
- Antigen on pathogen surface recognised
- Phagocyte move around pathogen, engulfing it (endocytosis)
- pathogen contained in phagocytic vacuole
- lysozome fuses with vacuole, digestive enzymes break down pathogen
- Phagocyte presents pathogenic antigen, activates immune system cells
- phagocyte becomes and antigen presenting cell.
What are Interferons?
They are Anti viral proteins which prevent viruses spread to uninfected cell
