Diseases and immunity Flashcards
Pathogen
any organisms that cause diseases
bacteria, fungi, protoctists
Transmissible disease
a disease in which a pathogen can be passed from one host to another
methods of transmission
- direct contact through body fluids (i.e. blood)
- indirect contact (air, food etc)
Defense against pathogens - Mechanical barriers
Physically block pathogens from entering the body
- skin, mucus membrane, fluids like urine/tears
Defense against pathogens - chemical barrier
Substances that trap & kill pathogens on body surfaces
- mucous membranes (lining of your gut/lungs)
- stomach acid
Immune system
detects and destroys pathogens after it`s gained entry to the body
Function of white blood cells
- phagocytosis
(white blood cells/phagocytes engulfs and destroys pathogens) - produces antibodies
(proteins which attach to pathogens and so mark them for destruction)
What does a vaccine do
injecting someone with a harmless version of a pathogen or its antigens, primes the immune system so that it can mount a rapid and large response to a pathogen entering the body
Antigens *
a substance that induces an immune response
Antibodies *
proteins produced by lymphocytes (type of white blood cell)
Once the antibody is attached to an antigen it can:
- mark the pathogen for phagocytosis
- cause the pathogen to break open and die
Memory cells *
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Vaccines *
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Antibodies *
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