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immune system - Coggle Diagram

- - - - self antigens
        
        cells and molecules that make up your own body
        
        self marker proteins
        
        MHC markers
        
        MHCII markers
        
        found on specialised immune cells
        
        MHCI markers
        
        expressed on all nucleated cells in the body
        
        Major Histo-Compatability Complex
        
        proteins on the surface of all nucleated cells
        
        each MHC marker contains a peptide that was bound to it in the cell
        
        peptide = degraded protein
        
        moves to plasma membrane and presents protein on outer surface
      - non-self antigens
        
        anything other than self
        
        antigens (foreign cells)
      - pathogen types
        
        pathogen = any organism or other biological entity that causes an infectious disease
        
        most pathogens contain unique non-self antigens or produce toxins that can be
        detected by the immune system
        
        cellular vs non
        
        cellular = living cellular organisms (bacteria, protists, fungi, animals)
        
        non-cellular = not living organisms but have the capacity to cause disease (viruses, viroids and prions)
        
        Extracellular bacteria do not have to enter host cells to reproduce, whereas intracellular bacteria do
        
        extracellular pathogen is one that cannot survive inside the phagocyte once it has been ingested
        
        multicellular eukaryotes
        
        (tapeworms, blood flukes)
        
        unicellular eukaryotes
        
        (giardia, plasmodium falciparum)
        
        eukaryotes (uni or multi)
        
        fungi
        
        usually superficial and non-life threatening
        
        Bacteria (prokaryotes)
        
        Intra + extra - cellular
        
        some rapidly reproduce and crowd out other tissues
        
        some kill outright / destroy
        
        exotoxins
        
        secreted substances that happen to be toxic to us
        
        endotoxins
        
        part of cell wall of gram-negative bacteria
        
        cause trouble when bacteria dies (toxins released by cell wall breaking)
        
        viruses
        
        composed of a nucleic acid (RNA or DNA)
        
        enclosed within a protein capsid
        
        some have phospholipid outer membrane
        
        contain enzymes necessary for their own reproduction
        
        because they dont metabolise, use ATP etc.
        
        to reproduce they take over a host cell
        
        insert their DNA or RNA
        
        viral contents are brought in via endocytosis
        
        host cell then produces new viral particles with that genetic info
        
        +sense
        
        -sense
        
        retrovirus
        
        intracellular pathogen
        
        prions
        
        misfolded protein
        
        nonliving
        
        no nucleic acids
        
        finds the normal version of itself (normally folded protein) and converts it to be a mifolded protein (prion)
        
        viroids
        
        infectious
        
        short
        
        single stranded RNA molecules
        
        20 kinds
        
        PLANTS ONLY
    - - 1st line of defense
        
        Plants
        
        bark
        
        layer of external dead material can prevent pathogens from getting into the plant
        
        waxy cuticle
        
        on outside of leaves, stops water seeping in and making plant soggy, helps keep pathogens out of the cell
        
        cellulose cell wall
        
        can help to keep pathogens from entering the cell
        
        chemicals
        
        some plants produce toxic chemicals to fend off pathogens and fungi (eg. mint oil)
        
        Animals
        
        physical barriers
        
        mucous membranes
        
        ciliated internal linings
        
        lined with mucous
        
        pathogens/ bacteria gets stuck in it
        
        1 more item...
        
        skin (intact)
        
        outer layer of skin is dead
        
        bacteria on skin dont see living tissue, therefore no new viral particles are made if viral DNA is inserted into the dead skin cells
        
        mechanical barriers
        
        reflexes
        
        sneezing
        
        coughing
        
        diarrhoea
        
        vomiting
        
        flushing action
        
        2 more items...
        
        evacuate bacteria before it enters the body/ crosses living tissue
        
        chemical barriers
        
        lysozyme in tears
        
        digests bacterial cell walls
        
        hydrochloric acid in stomach
        
        bacteria destroyed by acid (ph too acidic)
        
        microbiological barriers
        
        microbes in the human gut
        
        they outcompete pathogens for
        
        nutrients
        
        adhesion sites
        
        secrete antimicrobial chemicals that destroy other bacteria
        
        inreturn for this defense our immune system tolerates the presence the gut flora, mutualistic relationship
      - 2nd line of defense
        
        Innate Immune repsonse
        
        nonspecific
        
        cellular and molecular response
        
        response of the immune system once a pathogen has gotten through the first line of defense