12.5 The immune system + Phagocytosis Flashcards
what is an antigen?
a protein found on the surface of cells
how does the immune system recognise pathogens as foreign?
their antigens are identified as foreign which leads to an immune response
what are the two types of lymphocyte?
B and T
where are B lymphocytes produced from?
the bone marrow
where are the T lymphocytes produced from?
the Thymus gland
types of T lymphocytes
T helper
T killer
T memory
T regualator
T helper
bind to the antigen on an APC
stimulates production of interleukins which stimulates B cells
T killer
produce perforin which kills the pathogen by making holes in the cell surface membrane
destroys pathogens
T memory
form a part of the immunological memory by retaining the information on a foreign antigen
when the antigen is detected again, it divides to form T killer cells to destroy the pathogen
T regulator
suppress the immune system in order to control and regulate it
prevents an autoimmune response fromoccuring
what is an autoimmune response?
when the immune system attacks self cells
types of B lymphocytes
plasma cells
B effector
B memory
plasma cells
produce antibodies which are specific to an antigen
B effector
divide to form clones of plasma cells
B memory
provide immunological memory by remembering a specific antigen and when it encounters it again it divides into plasma cells
step 1 immune response
phagocytosis
phagocyte recognises the antigens on pathogen
opsonins bind to the antigens on the pathogen to make phagocytosis easier
phagocyte surrounds the pathogen and engulfs it to form a phagosome
lysosomes fuse with the phagosome to form a phagolysosome which breaks down the pathogen
the antigens on the pathogen are then presented on the phagocyte to form an APC
step 2 immune response
T lymphocyte activation
T helper cells bind to antigens on the APC which causes them to activate
the activation of T helper cells leads to clones of itself being formed
these clones:
- become T memory cells
- become T killer cells
- produce interleukins to stimulate B cells
step 3 immune response
B lymphocyte activation
activated B cells divide by mitosis to produce clones of plasma and B memory cells
plasma cells produce antibodies which are specific to the antigen on the APC
the antibodies then deal with the pathogen
if the body is infected again the B memory cells divide by mitosis into plasma cell clones which produce more of the specific antibody
how does an autoimmune disease work?
recognises the antigens on self cells as foreign
leads to the production of antibodies specific to these antigens
phagocytosis of self cells occurs
what is the immune response?
response to an antigen which involves the production of antibodies
