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In this video, we look at how the immune system protects us from pathogens. First we look at phagocytosis, then we explore antibodies and antitoxins.
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Hand abrasion By No machine-readable author provided. Berteun assumed (based on copyright claims). – No machine-readable source provided. Own work assumed (based on copyright claims)., Public Domain, https://commons.wikimedia.org/w/index.php?curid=385217
Music credit:
Deliberate Thought by Kevin MacLeod is licensed under a Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/)
Source: http://incompetech.com/music/royalty-free/?keywords=deliberate+thought
Artist: http://incompetech.com/
[Music] hi and welcome back to three sighs lessons cold okay by the end of this video you should be able to describe how the immune system protect us against pathogens in the last video we saw that the job of the nonspecific defense system is to stop pathogens from entering the body however sometimes this doesn’t work a good example is when you damage your skin like this now pathogens can invade the body and they can enter the bloodstream once inside the body pathogens can multiply and they damage healthy tissue for example bacteria can release chemicals called toxins which make us feel unwell so to protect us in cases happens the body also has the immune system and we’re looking at that in this video the immune system has got two main functions firstly the immune system destroys pathogens and any toxins they produce secondly the immune system protects us in case the same type of pathogen invade us again in the future so let’s take a look at how the immune system works the first key that you need to understand is that the immune system involves the white blood cells these have got three functions firstly white blood cells can ingest and destroy pathogens and I’m showing that here so this shows a white blood cell under pathogen the white blood cell detect chemicals released from the pathogen and moves towards it the white blood cell then ingests the pathogens like this the word ingest means take in in the exam make sure you say ingest and not eat now the white blood cell uses enzymes to destroy the pathogens this whole process is called phagocytosis and you could use that word in your exam now the second way that white blood cells can destroy pathogens is by making antibodies and we’re going to look at those now again it’s really important that you learn the details of how antibodies work antibodies are protein molecules produced by white blood cells so this white blood cell is releasing antibodies as you can see the antibodies stick to the pathogens this triggers the pathogens to be destroyed now there are two key factor antibodies firstly antibodies are extremely specific so for example if a person catches measles they’ll develop antibodies against the measles virus however those antibodies will only protect against the measles virus they will not protect against any other pathogen secondly antibodies can remain in the blood for a long time this means they can protect us in case we ever get infected again with the same pathogen okay now white blood cells protect us against pathogens in another way and we’re going to look at that now we said earlier that certain types of bacteria can release toxins these are chemicals which can make us feel unwell why blood cells can produce chemicals called antitoxins antitoxins stick to toxin molecules like this and they prevent them from damaging cells remember you’ll find plenty of questions on the immune system in my vision workbook and you can get that by clicking on the link above ok so hopefully now you should be able to describe how the immune system protect us against pathogens [Music]
