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Where can pathogens enter the body? CUTS IN THE SKIN THROUGH THE NOSE THROUGH THE EYES THROUGH FOOD How the body tries to stop them from entering. THESE ARE QUICKLY COVERED BY CLOTTED BLOOD (SCABS) TO KEEP INFECTION OUT. HAIRS IN THE NOSE TRAP DUST AND MICRO-ORGANSIMS. ANY WHICH ARE NOT STOPPED BY HAIRS ARE TRAPPED BY STICKY MUCUS IN THE AIRWAYS WHICH SLOWLY MOEVES THEM BACK TO UP THE THROAT WHERE THEY CAN BE SWALLOWED OR SPAT OUT. THESE PRODUCE CHEMICALS IN TEARS WHILL KILL BACTERIA ACID IN TE STOMACH KILLS MOST (BUT NOT ALL) BACTERIA. WHO ARE YOU?? (antigens) Once inside the body, micro-organisms are recognised as being foreign by our white blood cells. This means that our white blood cells know that they are not meant to be in the body and so they go about killing them. A cell from the body A pathogen. All the cells of our body are covered in protein markers called antigens. Every single cell in our body has the same type of antigen. When a pathogen enters the body the white blood cells notice that it has different antigens to normal body cells and therefore it does not belong in the body. The diagram above shows how antigens can be different. The 3 responses of white blood cells Why the response is successful Ingesting pathogens This one is self explanatory. The white blood cells swallow and digest the pathogens using enzymes. Producing antibodies These are chemicals which kill certain bacteria or viruses Producing antitoxins These counteract any toxins produced by pathogens. Medicines like painkillers help to treat the _______________ of disease but they do not kill the pathogens that cause the disease. Some _______________ can be used to kill bacteria inside our body. Others can be used to stop bacteria from reproducing. _______________ cannot be killed using antibiotics because viruses reproduce inside cells. Using drugs to kill viruses might damage the _______________ of our body and make us ill. If we are _______________ to a pathogen it cannot harm us. We can be vaccinated to make us immune to some pathogens. A vaccine contains dead pathogens. So jkscrg antibiotics cells immune symptoms viruses Vaccinations are made of dead or inactive forms of a pathogen. Once injected inside the body our white blood cells recognise their antigens as being foreign and go about making the correct antibodies to destroy these cells. If, in the future we become exposed to a live version of this pathogen our immune system can respond much more rapidly because our white blood cells “remember” how to make the correct antibody. This means the pathogen does not have the time to make us ill – we are immune! An example of a common vaccine is the MMR which vaccinates children against mumps, masles and rubella