Human Defence Mechanisms. Flashcards
Localised defence.
Phagocytosis, inflammation localising any break in the barrier and destroys invading organisms. Replacing or repairing damaged tissueZ
Human natural barriers
Skin flora: a natural population of organisms which compete with bacteria for nutrients.
Blood clotting: seal wounds
Ciliated mucus membranes, stomach acid, enzymes.
LYSOZYMES DAMAGE BACTERIAL CELL WALLS.
What is immunity?
A specific systemic response acquired during a lifetime.
Natural immunity.
Immunity occurring after a normal infection or antibodies passed from
Mum.
Artificial immunity
Injection of antigens to stimulate immune response or to stimulate combat.
Passive immunity.
The body receives antibodies from another source.
Active immunity.
Stimulation of immune system producing memory cells.
Cell mediated response.
A virus with viral antigens, enters and infects host cell. The host cell now displays chemical markers and viral non-self antigens.patticulr t lymphocytes recognise and bind to binding sites. Thelper cells also bind releasing cytokines which stimulate cloning. Dividing rapidly by mitosis they then undergo differentiation into t killer and tmemory cells. T memory cells help lunch a futures
More rapid attack. T killer cells bind and release perforin to foreign cells.
Humoral response.
Macrophage engulfs foreign material. Displays non self antigens. A b lymphocyte recognises and binds, a t helped cells does the same and releases cytokines which make the other one divide rapidly by mitosis and differentiate into n memory cells which help to launch a motor rapid attack in the future. And b plasma cells which secrete antibodies into circulation
Antibodiesz
Glycoproteins - immunoglobulin group. Produced by lymphocyte. 2 identical binding sites Form an antigen-antibody complex. Formed from 4 polypeptide chains Protect body from foreign material.
Antibody structure
Heavy polypeptide chain
Hinge region.
Light polypeptide chain
Antigen binding sites
Antibodies have what function???
Immobilise antigens allowing destruction by phagocytosis.
Agglutinate antibodies together
Neutralise toxins produced by bacteria.
Lymphocytes originate where. B lymphocytes mature where; activated where for t lymphocytes.
Stem cells in bone marrow, spleen and lymph nodes, t lymphocytes activated in tepid gland.
Invasion by corresponding antigen causes…
Proliferation of t lymphocytes
3 stages of HIV and aids.
Stage 1 infected person HIV+ with no symptoms. ( possible flulike symptoms pass in two week)
Stage 2 infected person feels unwell due to low t helper cell count. (thrush, herpes, pneumonia, diarrhoea)
Stage 3 aids with very low t helper cell count. ( extreme weight loss, pneumonia, chronic diarrhoea, tuberculosis, skin and lymph cancers)
HIV structure.
RNA, two strands of genetic material.
Protein on outer surface allows virus to attach to human receptor cell Molecules.
Reverse transcriptase enzyme allows viral RNA to be used as a template to produce viral dna
HIV advantages for mutation
Outruns immune system and targets helper t cells ad macrophages
When do HIV use reverse transcriptase and what does it do?
Before inserting itself into human DNA. And allows viral RNA to be used as a template to produce viral DNA.
HIV progression.
1-10 latent year period, HIV progressed to aids when body can’t fight off other opportunistic infections, like tuberculosis.
Aids victims also suffer from non Hodgkin lymphoma. And karposis sarcoma.
How is HIV tested.
Antibiotics.
Vaccination forms.
A vaccine may be an attenuated or killed form of pathogen. Or an inactive toxin from a bacteria.
What is vaccination a medical example of?
A preventative medicine. Of top few are vaccinated then there will be an epidemic, if lots do the the pathogen will likely die out.
Draw the vaccine graph.
First response lasts 5 days
Time gap between exposures. Secondary response lasts 5 days and jumps up on two.
Properties of secondary response.
Lower level of antigen, shorter latent period. Higher concs of antibodies produced and duration of concs is longer.
