KA 5: parasitism: defence against parasitic attack Flashcards
describe immune response in mammals
has both non-specific and specific aspects
list non-specific defences
NON-SPECIFIC DEFENCES
- physical barriers
- chemical secretions
- inflammatory response
- phagocytes
- natural killer cells destroying cells infected with viruses
describe the epithelial tisue block
- epithelial tissue blocks the entry of parasites
- hydrolytic enzymes in mucus, saliva and tears destroy bacterial cell walls
- low pH environments of the secretions of stomach, vagina and sweat glands denatures cellular proteins of pathogens
what do injured cells releasing signalling molecules result in?
NON-SPECIFIC DEFENCES
enhanced blood flow to the site, bringing antimicrobial proteins and phagocytes
how are parasites killed?
NON-SPECIFIC DEFENCES
using powerful enzymes contained in lysosomes, by engulfing them and storing them inside a vacuole in the process of phagocytosis
describe the function of natural killer cells
NON-SPECIFIC DEFENCES
can identify and attach to cells infected with viruses, releasing chemicals that lead to cell death by inducing apoptosis
describe specific cellular defences
SPECIFIC CELLULAR DEFENCES
a range of white blood cells constantly circulate, monitoring the tissues
what happens if tissues become damaged or invaded?
SPECIFIC CELLULAR DEFENCES
cells release cytokines that increase blood flow resulting in non-specific and specific white blood cells accumulating at the site of infection or tissue damage
what do the different lympocytes in mammals each posses?
SPECIFIC CELLULAR DEFENCES
a receptor on its surface, which can potentially recognise a parasite antigen
what triggers the selection of a lymphocyte to then divide and produce a clonal population of this lymphocyte?
SPECIFIC CELLULAR DEFENCES
binding of an antigen to a lymphocyte’s receptor
what will some selected lymphocytes produce?
SPECIFIC CELLULAR DEFENCES
antibodies
what will other selected lymphocytes induce?
SPECIFIC CELLULAR DEFENCES
apoptosis in parasite-infected cells
what regions do antibodies possess and what does this variable region give the antibody?
SPECIFIC CELLULAR DEFENCES
where the amino acid sequence varies greatly between different antibodies
specificity for binding antigen
what happens when the antigen binds to this binding site?
SPECIFIC CELLULAR DEFENCES
-antigen-antibody complex formed
-results in inactivation of the parasite, rendering it susceptible to a phagocyte, or it can stimulate a response that results in cell lysis
-memory lymphocyte cells are also formed
what happens due to initial antigen exposure?
SPECIFIC CELLULAR DEFENCES
produces memory lymphocyte specific for that antigen
