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worst presentation on Immune System's 3rd Line Of Defense ever
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Immune System
Third Line of Defense – Specific Immunity
called into action when nonspecific methods are not enough and infection becomes widespread
FUNCTION mounts attacks against
specific foreign substances
specific foreign
substances
FEATURES………………
Self/non-self discrimination - it normally distinguishes between self and non-self and only reacts against non-self.
non-self
When a nonself (foreign) body is detected, mitotic activity in B and T lymphocytes is stimulated
While mitosis is occurring, the daughter populations become subdivided into…
Effector cells when fully differentiated,
they will seek and destroy foreign materials
Memory cells
become dormant, but can be triggered to rapid mitosis if pathogen encountered again
Memory - it demonstrates memory. The immune system "remembers" if it has seen an antigen before and it reacts to secondary exposures to an antigen in a manner different than after a primary exposure. Generally, only an exposure to the same antigen will trigger this memory response.
Specificity - there is a high degree of specificity in its reactions. A response to a particular antigen is specific for that antigen or a few closely related antigens.
CELLS INVOLVED
………………
Macrophages engulf foreign objects inform T lymphocytes at a
specific antigen is present
Helper T cells
produce and secrete chemicals which promote large numbers of effector and memory cells
Cytotoxic T cell T lymphocytes
that eliminate infected body cells and tumor cells
B Cells produce antibodies (secrete them
in the blood or position them on their cell surfaces)
The process can be simplified into three
events:
(1) Recognition of a specific invader
SPECIFIC INVADER
(2) Repeated cell divisions that form huge lymphocyte populations
(3) Differentiation into subpopulations of effector and memory cells
Effector Memory