4.1.1 Communicable Disease,disease Prevention And The Immune System Flashcards
Describe the differences between infectiuos and non infectiuos diseases
Infectiuos - involves the transfer of a pathogen
Non infectiuos - does not involved pathogen and are not transfered between organims
What types of pathoegns are there
Bacteria- prokaryotic cells that multiply rapidly,often causes harm by releasing toxins
Fungi- often growth projections called hyphae which can release spores
Viruses - invade cell machinery for replication and burst cells to spread
Protoctist - act as parasites feeding off the host cells
Define direct and indirect transmission
Direct- physical contact, faecal oral route, droplet,infection or transmission as spores
Indirect - Living vector to transmit the pathogen such as in malaria
State 2 plant features that make plants excellent host for pathogens
Plants photosynthesise to produce their own sugars and therefore, are a good source of nutrition for pathogens or vectors.
Plants do not have immune systems comparable with that of animals to fight off invading pathogens
State and explain 4 examples of passive plant defence mechansims
Cellulose cell wall acts as a physical barrier but also releases anti-pathogenic chemicals. Cell walls are thickened with the phenolic compound lignin, which is waterproof and almost totally indigestable, prevent pathogen entry.
Plants waxy cuticle prevents water from collecting on the surface of plants, pathogens struggle to survive.
Callose deposition blocks the flow in the sieve tube and prevents the spread of pathogens via the phloem
Outline how inflammation contributes to the bodys immune response
Mast cells and damaged white blood cells in the damaged connective tissue and around blood vessels near the damaged tissue releases such as histamine. Histamine causes the blood vessels to dilate, increasing blood flow to the area of damaged tissue. Histamine also increases capillary peremability, enabling the leak of plasma fluid , WBC and antibodies from the blood into the damaged tissue, causes swelling. Pathogens are subsequently targeted.
Describe 2 general features of inflamation that help to minimise the impact of an infection
Increase blood flow leads to increases WBC level
Excess tissue fluid will drain into lympathic system where it will come into contact with lymphocytes
Explain how macrophage is able to remove and destroy gluten fragments
Macrophage will destroy the gluten fragments by phagocytosis. Engulfs the gluten fragment. Fragment is then digested by enzymes/lysosomes
Describe the mechanism of T helper cell activation
After a macrophage engulfs an antigen, it can attach a protein to this antigen and display it on its CSM as a non-self antigen. Macrophages displaying non self antigens become antigen- presenting cells
T helper cell with a complementary shaped CD4 receptor on its surface can bind to this antigen on the antigen presenting cell. Activavtion of T helper cells
Describe the role of T killer cells in the immune resposne
Recognise cells that present non self antigens on their surface and release chemicals that destroy these cells
Describe the function of B memory cells
Long lived cells that remajn dormant in the lympathetic system
Second meeting with their target antigen, rapidly divide and produce antibodies, destroy antigens much more quickly compared to first exposure
Explain the major difference between primary and secondary immune response
Primary immune response is slower than the secondary immune response
Primary response there are no memory cells present specfic to the pathogen
T helper cells must be activated by the antigen from the pathogen, then activate a B cell to produce antibodies which destroy the pathogen. Memory cells form
Explain the difference between antigen and antibodies
Antigens are proteins found in the membrane of pathogens that trigger immune resposnes,whereas antibodies are proteins produced by plasma cells in the specfic response
Explain how cells of the immune system determine self from non self molecules
Each cell in the body has a specfic surface molecule that identify it as ‘Self’ or ‘non self’
Non self substances have antigens that can be recognised by the cells of the immune system,producing an immune resposne . These antigens are usually (glyco) proteins, have specfic teriary structure which can be used by the cells of the immune system to detect if the substance is ‘self’ or ‘non self’
Explain 2 roles of antibodies in eliminating pathogens
Antibodies can bind to antigens and act as opsonins flagging them for phagocytosis
Bind to multiple pathogens together, they have 2 variable regions allowing pathogens to be agglutinated
