3.6 Flashcards
m what is in the immune system
a large number of lymphocytes each with a single type of membrane receptor
why do lymphocytes only respond to specific pathogens
the membrane receptor is specific for one antigen on the invading pathogen
what is an antigen
a type of protein found on the surface of pathogens
what results in a clonal population
the binding of the membrane receptor and the antigen leads to the lymphocyte repeatedly dividing
what is a clonal population
multiple of the same lymphocytes are produced
what happens to the cells produced in a clonal population
some are used immediately and some are kept as memory cells for future use
what are antibodies
a y shaped molecule with a specific receptor
how do b lymphocytes work
they produce antibodies which bind to antigens inactivating the pathogen , which is then destroyed by phagocytes
what happens when B lymphocytes respond to antigens on substances that are harmless to the body
it results in an allergic reaction
(hypersensitivity)
how do t lymphocytes work
they destroy infected body cells by recognising antigens of the pathogen on the membrane and inducing apoptosis
give a description of apoptosis
T lymphocytes attach to infected cells and release proteins they diffuse into cell and tell the cell to self destruct , cell dies then is removed by phagocytosis
how do t lymphocytes distinguish between the self antigens and non self antigens
they have specific surface proteins on its surface
why is the ability to distinguish between self and non self important
you can develop an auto immune disease as your good cells are getting killed
give an example of auto immune diseases
type 1 diabetes
rheumatoid arthritis
how do memory cells make a secondary response
much more rapid response
antibodies are at a higher concentration
it’s maintained for a longer time
