Mind Map by , created over 5 years ago

Disease and Immunity

Created by lilydellar over 5 years ago
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Unit One
1 Disease and Immunity
1.1 Disease
1.1.1 Causes of Disease Infectious Pathogens e.g. bacteria Non infectious Body malfunctioning e.g. cancer Lifestyle or environment e.g. malnutrition Coronary Heart Disease (CHD) Affects heart Lifestyle factors that increase risk of developing CHD Poor diet - high intake of saturated fats or salt Smoking Lack of exercise Leads to high blood pressure - damaging the heart and blood vessels Excessive alcohol intake Cancer The result of uncontrolled cell division Factors that increase the risk of many types of cancer Smoking - mouth, throat and lung cancer Excessive exposure to sunlight - skin cancer Excessive alcohol intake - liver cancer
1.2 Pathogens
1.2.1 "An organism that causes a disease"
1.2.2 Types of pathogen Fungi Bacteria Virus
1.2.3 Entry into the body Gas exchange system breathing in air containing pathogens (p) p get trapped in mucus lining the lung epithelium cells have cilia that beat and move the mucus up the trachea to the mouth - where removed HOWEVER some pathogens are still able to reach the alveoli where they can invade cells and cause damage The skin Damaged skin = pathogens on surface can enter bloodstream Blood clots and dries, forming scab to prevent pathogens from entering HOWEVER some may get in before scab forms Digestive system Eat or drink something that contains pathogens Most of them will be killed by acidic conditions of stomach HOWEVER some may survive and pass into the intestines where they invade cells of gut wall
1.2.4 How pathogens cause disease Production of toxins Cell damage Done by... Rupturing to release nutrients Breaking down nutrients inside the cell for own use Starves and eventually kills cell Replicating inside the cell; bursting them when they're released
1.3 Immune Response
1.3.1 If a pathogen gets past your first line of defences, the immune system kicks in
1.3.2 Activating the immune response Pathogen invades body -> molecules on surface (antigens) are identified as foreign -> activates cells in immune system Antigens = a protein (or polysaccharide) that causes an immune response ANTIbody GENerator
1.3.3 Four main stages of immune response (1) phagocytosis A phagocyte is a type of WBC that carries out the engulfment of pathogens Found in the bloody and in tissues and are the first cells to respond to a pathogen inside body The phagocyte recognises the antigens on a pathogen Cytoplasm of phagocyte moves round pathogen -- now contained in phagocytic vacuole Lysosome fuses with the vacuole, releasing lysosomal enzymes which break pathogen down phagocyte presents pathogen's antigens on its surface to activate other immune system cells (2) T-cell activation T-Cell = WBC Has proteins on its surface that bind to antigens presented by phagocytes, activating T Cell Different t-cells respond in different ways Helper T Cells activates B Cells Killer T Cells Destroy cell by attaching to antigens on pathogen Suppressor T Cells Stops the immune response (or it'll get out of hand) Memory Cells (3) B-cell activation & plasma cell production B-cell = WBC covered with antibodies (that bind with antigens) antigen-antibody complex activates B-cell; which divides to produce more b cells called plasma cells (clones) Memory Cells remember specific antigen from primary response bind to it second time around = immune; quicker and stronger response (4) Antibody production plasma cells secrete loads of antibodies Functions coating pathogen making it easier for phagocyte to engulf it coating it - preventing it from entering host cell Binding & neuatrisling (inactivating) toxins produced by pathogen
1.3.4 Antibody structure made up of chains of amino acid monomers linked by peptide bonds Specificity of antibody depends on its variable region (different shape due to different amino acid sequences) Each antibody is complementary to one specific antigen
1.3.5 Cellular response T-cells
1.3.6 Humoral response B-cells
1.3.7 Primary & secondary response Primary B-cells do their antibody thing and eventually overcome infection Secondary memory cells produced from primary response go go go production of antibodies is quicker and greater
1.4 Vaccines
1.4.1 contain antigens that cause your body to produce memory cells against a particular pathogen, without causing any disease
1.4.2 Immune
1.4.3 Herd immunity fewer people to catch it from, so those not vaccinated are less likely to catch the disease
1.4.4 The antigens are either free or attached to a dead or weakened pathogen
1.4.5 taken orally or injected disadvantage for taking orally = can be broken down by enzymes in the gut or molecules of vaccine may be too large to be absorbed into the blood
1.4.6 Ethical issues Tested on animals Testing on people can be risky Some people don't want to take vaccine due to side effects but still protected due to herd immunity some see this as being unfair outbreak of a new disease - who would receive the vaccine first?
1.5 Antigenic Variation
1.5.1 some pathogens can change their surface antigens (changes in the genes of a pathogen form different antigens) memory cells produced from primary response do not recognise the antigens Immune system starts from scratch This takes time and so you get ill again
1.5.2 Hard to develop vaccines against pathogen
1.5.3 Influenza virus
1.6 Monoclonal Antibodies
1.6.1 they are antibodies produced from a single group of genetically identical b-cells (plasma cells) - so identical in structure
1.6.2 can make monoclonal antibodies that bind to anything you want - they will only bind to this target molecule
1.6.3 Pregnancy tests, AIDS & anti-cancer drugs (pg 19-20)
1.6.4 Ethical issues animal rights issues
1.7 Validating New Knowledge About Vaccines and Antibodies
1.7.1 when a study presents evidence for a new theory it's important that other scientists come up with more evidence to validate the theory i.e. repeat the study MMR Vaccine (pg 21) Herceptin - monoclonal antibodies (pg 22)
1.7.2 Using scientific knowledge to make decisions