Immune System Flashcards
What is a disease?
A condition that prevents the body or a part if it from working
How are diseases caused?
By micro-organisms (pathogens) entering the body and feeding and reproducing in it, and damage/ poison the body by excreting toxic waste substances called toxins
What are the main causes of disease?
Very small micro-organisms. eg. Virus and bacteria
What are physical barriers against disease?
Skin and membranes of the body
What happens when the barrier is damaged?
White blood cells take over the defence of the body
How do phagocytes work?
- Phagocyte recognises the pathogen
- Phagocyte engulfs pathogen in a process called phagocytosis
- The lysozymes containing enzymes move towards the pathogen
- Enzymes break down pathogen
- Useful materials absorbed
- Waste products are removed from the phagocyte
What is phagocytosis?
Phagocytes are a type of white blood cell that engulfs and digests pathogens that they encounter, this is called phagocytosis
What do lymphocytes produce?
Antibodies
How do lymphocytes work/
- Lymphocytes detect pathogen’s antigens
- Lymphocytes identify the correct type of antibody to make, which is complementary to the pathogen’s antigen
- Lymphocytes release large numbers of correct antibodies
- Pathogens either clump together resulting in death or the antibodies trigger phagocytes. Some pathogens can even burst
- Lymphocytes produce cells that produce lots of the antibodies very quickly if they detect the same pathogen again, these are called memory cells.
What are some antibodies used for?
They are specialised to combat toxins, chemicals released by the pathogen who cause cell damage. they are called anti-toxins
How do vaccinations work?
- The body is given a vaccine, which is a dose if the pathogen, normally by injection
- This does is either dead pathogens or parts of a pathogen’s cells surface
- This stops the pathogen from causing disease
