Defence Mechanisms Flashcards
What is an infection?
The interaction between the pathogen the body’s various defence mechanisms
What is an example of an immediate and general defence?
The skin forming a barrier to the entry of pathogens and phagocytosis
What are 3 characteristics of defences that involve lymphocytes?
1)more specific
2) Less rapid
3) Longer lasting
What response involves T cells?
Cell mediated
What response involves B cells?
Humoral response
Why do body cells need to be able to distinguish between the body’s molecules and foreign molecules?
So the lymphocytes don’t destroy the organism’s own tissues
How do lymphocytes distinguish between normal body cells and invading cells?
Enormous variety and high specific tertiary structure of proteins on the cell surface membrane
What is the first stage of threat removal?
The immune system identifying non-self molecules by help of outer cell proteins
What 4 things does the immune system recognise as a threat?
1) pathogens
2) Toxins
3) Nonself material
4) abnormal body cells
Why are organ transplants often attacked by the immune system?
Recognises the organs as non self so tries to destroy the transplant
What 3 ways can reduce the risk of organ transplants being rejected?
1) donor tissues must be matched closely to recipient
2) Immunosuppressant drugs to stop immune response
3) matches from relatives
What is clonal selection?
When lymphocytes are stimulated to divide to build up its numbers to an effective level
What collides with cells in the foetus?
Lymphocytes
How come they only collide exclusively with the body’s own material?
The mother and the placenta stop the foetus getting infections
What lymphocytes undergo apoptosis?
Whose receptors fit exactly onto the body cells’ receptors
Who responds to self antigens
