U4 AOS1 Chp 5 Definitions Flashcards
VCE Unit 4 AOS 1 Biology Chp 5 content from Jacaranda Biology Textbook
Antigens
Unique molecules or parts of molecules that can often elicit an immune response, through the adaptive immune response and so play a crucial role in immunity
Allergens
Any antigen that causes the immune system to produce an abnormal and inappropriate overaction when a person is exposed to it
Allergic reactions
specific type of immune response in which the immune system overreacts to a normally harmless substance.
Clonal deletion
2 stage process of selecting T lymphocytes that recognise MHC proteins and eliminating those that react to self antigens
Self tolerance
Inability to respond to self antigens (if this breaks down = autoimmune disease)
MHC – 1 Markers
Nucleated cells have these to recognise as self.
MHC – 11 Markers
Markers on leukocytes (white blood cells) and antigen-presenting cells that present antigens to the immune system
Pathogen
Agents that cause disease
Primary pathogen
cause disease any time they are present
Opportunistic pathogen
only cause disease when the hosts defences have been weakened
Exotoxins
secreted toxins
Endotoxins
parts of the outer membrane that are released when bacteria die
Antigenic variation
mechanism by which surface antigens change
Anthropods
invertebrates with external skeletons that are able to transmit or cause disease to humans
Viron
composed of genetic material enclosed in a protein
Antigenic drift
some viruses constantly make minor changes to the antigens on the surface
Viroid
type of self cleaving RNA enzyme composed of short circular RNA strands that lack protein coat
Prions:
infectious agents composed primarily of proteins that are abnormal normal cell protein produced by gene mutations
Innate immunity
nonspecific defence mechanisms that come into play immediately of an antigen’s appearance in the body
Adaptive immunity
refers to antigen-specific immune response that operates only after innate immune defences are overwhelmed.
surfactants
coat the pathogens making it easier for them to be eliminated by macrophages
normal flora
nonpathogenic bacteria found on the skin and in the mouth, nose, throat, lower part gastrointestinal tract and urogenital tract in healthy individuals
Toll-like receptors (TLR)
pattern recognition molecules on leukocytes that are able to recognise microbial molecules PAMPS
Pathogen-associated molecular patterns (PAMPs)
Microbial molecules that are common to a range of pathogens
Phagocytes
Leukocytes that engulf and break down pathogens via phagocytosis including macrophages, neutrophils and dendritic cells