An interaction between the pathogen and the body's various defence mechanisms
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What is immunity?
The way in which white blood cells (and the antibodies that some of them produce) enable the body to fight infection
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What are the two types of immune respsonse?
Specific and non-specific
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What two things are part of the non-specific response?
- Physical barriers - Phagocytosis
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What two things are part of the specific response?
- Cell mediated response - Humoral response
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What type of lymphocyte is involved in cell mediated response?
T lymphocytes
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What type of lymphocyte is involved in humoral response?
B lymphocyte
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What type of cells are lymphocytes?
White blood cells
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What are the two main differences between specific and non-specific responses?
- Non-specific responses are immediate whereas specific responses are not - Non-specific responses are the same for each pathogen whereas specific responses are specific for each pathogen
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Why must lymphocytes be able to distinguish between self and non-self cells?
Otherwise they would destroy the organisms own tissue
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How can cells be distinguished?
Each type of cell has specific molecules on its surface that identify it
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Which surface molecules are the most important in recognising foreign material and why?
The proteins because they have enormous variety and a highly specific tertiary structure- it is this specific 3D protein structure that makes each cell identifiable
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What four types of cells must the immune system be able to identify?
- Pathogens - Non-self material - Toxins - Abnormal body cells
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Why can donor transplants be rejected by the body?
They come from another individual, and even though they may be of the same species it is still recognised as non-self material by the body's immune system, hence the body tries to attack it
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Where do all the specific lymphocytes come from when non-self material invades our bodies?
They already exist in our bodies, all ten million types
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Why si it useful that so many lymphocytes already exist in our bodies?
There is a high probability that when a pathogen invades our body that there will already be a lymphocyte with a specific protein on its surface that is complementary to one on the pathogens surface
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What is clonal selection?
When a lymphocyte is stimulated to rapidly divide by mitosis when in contact with its complimentary pathogen to increase its numbers enought to destroy the pathogen
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In the fetus, how are lymphocytes programmed to only respond to non-self cells?
- In the fetus, all the lymphocytes are constantly colliding with other cells - Infection in the fetus is rare due to the protection from the placenta - So lyphocytes will collide almost exclusively with self material - the lymphocytes receptors that
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fit those of the bodys own cells either die or be suppressed
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How are lymphocytes that respond to self material eliminated in adults?
Lymphocytes are produced in the bone marrow in adults and initially only encouter self-antigens and any lymphocytes that show an immune response to self material undergo apoptosis before they differentitae inot mature lymphocytes, hence
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only the lymphocytes that respond to non-self material will appear in the blood
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Other cards in this set
Card 2
Front
What is immunity?
Back
The way in which white blood cells (and the antibodies that some of them produce) enable the body to fight infection
Card 3
Front
What are the two types of immune respsonse?
Back
Card 4
Front
What two things are part of the non-specific response?
Back
Card 5
Front
What two things are part of the specific response?
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