Immune Response Flashcards
fr
Distinguish between non-specific defences and immune responses.
Non-specific defences act in a general way against a variety of pathogens, whereas immune responses ARE specific; they make defences against a specific pathogen (i.e what vaccines are for).
Describe innate immune responses.
It uses attacking cells and molecules that breach the first line of defence (that being skin). They act very quick and do not form antibodies.
Give some examples of non-specific defences in vertebrates.
Internal; enzymes in mucus, sweat and tears
External; Histamines
- Phagocytes
- Complement system
- Interferons
- Pyrogens
Describe Histamines.
A chemical found in some of the body’s cells; causes runny nose, sneezing. (hence, why some people need anti-histamines to stop sneezing!)
Describe interferons.
Proteins made by host cells in response to the presence of pathogens. They communicate between cells to set up defences.
Describe pyrogens.
Chemicals that interfere with the functioning of the hypothalamus (responsible for temperature control). This is what induces fever to kill off pathogens.
Describe antigens.
Antigens evoke an immune response. Antigens that elicts an immune response is known as an immunogen. Allergens are antigens that cause an allergic reaction.
Barriers to infection?
Physical Barrier: Skin, bark
Chemical Barrier: lysozyme enzymes in saliva and other body fluids.
Microbiological Barriers: Microflora (colonies that keep pathogenic cells under control)
Describe the active immunity response.
It is specific and involves memorising the pathogen to form antibodies. (B lymphocytes and T lymphocytes).
Describe lymphocytes.
Subpopulations of white bloodcells produced in bone marrow to take action in the immune system. B cells and T cells.
Distinguish between B cells and T cells.
B cells produce large quantities of antibodies when stimulated by particular antigens. T cells act against virus and cancer cells and transplanted tissue. T cells have passed through the thymus where they are sensitized.
What can antigens do?
They can bind to antibodies or T cell receptors. They stimulate lymphocytes to start immune responses.
Describe antibodies.
They are specific proteins by lymphocytes that react with particular antigen molecules. They are released in blood and lymph fluid. They reverse engineer their protein structure to complement the foreign cell.
Describe the mechanisms of adaptive immunity.
Humoral; involves B cells producing antibodies against specific antigens which is released in extracellular fluid.
Cell-meditated; involves T cells and phagocytes which recognise foreign cells and mount a direct attack against them.
Describe the role blood platelets.
Plays a major role in haemostasis.They maintain surveillance of blood vessel continuity, filling small gaps that
can form between endothelial cells that make up the lining of the vessel wall. They form the primary haemostatic plug when vessel injury occurs, and secrete growth factors to stimulate healing after injury.
