IMMUNITY Flashcards
First line of defense
innate, non-specific
prevents the entry of pathogens into body
Physical barriers
stops pathogens from entering body
i.e INTACT skin, nasal cavity, ears,
Chemical barriers
destroys pathogens on the outer body surface, openings and linings
i.e saliva enzyme (lysosome), stomach acid, tears
Microbiological / microbiota barriers
prevents the growth of pathogenic microbes good bacteria present in the body
i.e acidic secretions, stomach acid
Plant barriers
physical
waxy coating, thick bark, spikes and thorns
chemical
antimicrobial compounds
antifungal compounds
Second line of defence
innate, non-specific
destroys all general invaders of the body, does not target specific antigens
Cell mediated immunity
cells of the immune system = white blood cells
Phagocytes
ingest and destroy antigens by phagocytosis
recognise patterns on antigens, not specific antigens
Macrophages
big eaters
antigen-presenting
found in tissue
Neutrophils
first responders
first cells to arrive at infection site (attracted to foreign material by chemical signals)
found in blood
Dendritic cells
found in tissue, reside/patrol skin and mucousal surfaces
can migrate to lymphe nodes
antigen-presenting
Phagocytosis
- phagocyte recognises microbe via receptor
- phagocyte engulfs microbe via endocytosis
- vesicle containing microbe binds with lysosome
- lysosome empties digestive enzymes into vesicle
- enzyme digests microbe
- particles are released from phagocyte
Eosinophils
parasite destroyers
present in respiratory, gastrointestinal and urinary tract
defends against larger parasitic agents
granules with tocix chemicals and histamines
Natural killer (NK) cells
found in blood and lymph
kills virus infected cells through apoptosis
attacks cells that lack self markers, or have missing/abnormal MHC markers
NK cells - Degranulation
NK cells recognise abnormal cells and release perforin (punches holes in cell membrane) and proteases (triggers apoptosis)
Mast cells
found in tissue close to external environment
mediates inflammatory/allergic response
granules contain cytokines (increases permeability) and histamine (attracts other immune cells)
Humoral immunity
immune response in humors (body fluid, i.e blood, phglem)
Complement proteins
innactive enzyme in blood that assists in the function of immune cells
activated after direct contant with molecules on the surface of a pathogen
activates other complement proteins - causes inflammation or lysis and enhances phagocytosis
Complement proteins - Opsination
marking pathogens and makes them more susceptible to phagocytosis
Complement proteins - Chemotaxis
chemical signals that stimulates movement of cells
attracts immune cells to site of infection
Complement proteins - Lysis
membrane-attack complex (MAC) forms on plasma membrane of pathogen
Intereferons
virally infected cells release interferons to prepare neighbouring cells for possible attack
cytokines - signalling proteins
antigen
a substance that illicits an immune response
self and non-self antigens
self: tolerated by the body
non-self: foreign and illicits immune response
