Immune system overview L3 Flashcards
goals of immune system
to control, protect and kill
challenges of immune system
- distinguish between harmful and harmless microbes, like food and pollen
- detect pathogens
- control strength of immune response to not cause damage to healthy cells
takes a whole team to do this
role of barriers
these are 1st line of defence
protect and prevent pathogens from entering and causing disease
mechanical barrier examples
tight junctions of epithelial cells - preventing them getting in
sweat, mucus, cilia - push and get rid of pathogens
chemical barrier examples
skin = fatty acids
gut = low pH, enzymes
tears = enzymes
lungs = pulmonary surfactants and alpha-defensins
microbiological barrier examples
normal microbiota
- acts as competition
mucosal barrier
the largest barrier
- GI, reproductive and respiratory tracts
HIV, rubella, rhinovirus, influenza, tapeworm can evade this though
what happens if something gets through barriers?
If there is a break in the barrier like a skin cut, bite, or burrowing of parasite
- pathogen is in and this then triggers the immune response
innate immunity goal
1st responder of pathogen in body, buys time for adaptive response and responds to danger signals (breaks in the barrier
innate immunity overview
very general and not specific
always on and rapid response
inmates immune response
recruits cells to infection site to cause inflammation
communicates with other cells
tells adaptive when to respond
innate immunity cells
macrophages
neutrophils
basophils
NK cells
mast cells
innate killing mechanisms
phagocytosis
killing infected cells via NK
complement proteins
cytotoxic secretion
adaptive response overview
very specific and can identify strains and cells
needs to be switched on
coordinates immune response
requires time to produce specific cells - slow response
has immune memory
B cells
produce Antibodies, neutralisation of microbes
marks cells for destruction
very specific to individual pathogens
links innate and adaptive together
3 types of T cells
Th cells
- activates cells, communicates, amplifies innate, coordinates response
Treg - turns off immune response
CTL - cytotoxic, kills infected cells
communication cytokines
chemical messengers
system response/communication
easy and quick signal amplification
difficult to control and be precise
efficient is increased by lymph nodes
cell to cell communication
ligands and receptors
local response
need to be in contact with cell
very precise
efficiency increased by lymph nodes
lymph nodes and spleen
coordinator sites for immune response
very important
second memory
has stronger and faster adaptive response
memory of B and T cells
