Please enable JavaScript.
Coggle requires JavaScript to display documents.
B5 Revision: Immunisation and The Immune System (Immunisation: (You can be…
B5 Revision: Immunisation and The Immune System
Immune System:
Immune system destroys pathogens that enter the body
White blood cells travel through the blood searching for pathogens to then respond:
Consumes them:
Non-specific response. White blood cells eat foreign (antigens on surface of pathogens) cells and digest them
Phagocytosis
Producing antibodies:
B-lymphocytes are the white blood cells that response to a specific pathogen.
All pathogens have antigens on their surface. When B-lymphocytes come across the antigen, they will start to produce antibodies
These antibodies bind to invading cells so they can be found and destroyed by other white blood cells
Antibodies produced are specific to the pathogen and can't lock on others
The antibodies reproduce rapidly and are carried around he body to find similar pathogens
Key words:
Antigen:
A molecule (protein) found on the surface of a cell that triggers an immune response
Antibodies:
A protein produced by white blood cells in response to the presence of an antigen
Lymphocytes:
Type of white blood cell that can produce antibodies or antitoxins against microorganisms
Memory Lymphocytes:
Immune system slow first time pathogen invades body, response is slow as there aren't many b-lymphocytes to make the antibody
Some white blood cells are called memory lymphocytes are produced in response to a foreign antigen
Remembers a specific antigen
Stays in the body for a long time
Person is now immune to the pathogen as body able to respond quicker
If the same pathogens enter the body again, there are more cells that would recognise it and produce antibodies against it
Because the secondary response is so quick, you are less likely to show symptoms
Immunisation:
You can be immunised against some diseases (e.g. measles) which stops you from getting ill in the first place
Injecting a vaccine into the body which contains small amounts of dead or inactive pathogens that carry antigens (antigenic)
Dead pathogen causes white blood cells to produce antibodies which target them even though the pathogen is harmless
E.g. against measles, mumps and rubella using MMR vaccine
Antigen will trigger production of memory lymphocytes so if that type of live pathogens invades the body the memory lymphocytes can quickly mass-produce antibodies to destroy the pathogen in a secondary immune response
Pros and Cons of Immunisation:
Pros:
Immunisation has helped many infectious diseases that used to be common in UK (polio, measles, rubella, mumps) Smallpox no longer occurs and polio has fallen by 99%
Outbreaks of diseases (epidemics) can be prevented if many people have been immunised
Fewer people to pass it on to (herd immunity)
Cons:
Immunisation doesn't always work
Could have a bad reaction to a vaccine (e.g. swelling, fever and seizures)