unit 3.5: non-specific body defences Flashcards
(17 cards)
what are the first defences against invading pathogens
physical and chemical barriers
what is an example of a physical barrier
epithelial cells the cover the inner cavities and cover the bodies surfaces, they are closely packed cells
what is an example of chemical secretions
tears
saliva
mucus
stomach acid
sweat
how does sweat prevent pathogens from entering the body
by keeping the skin pH too low for microbes to thrive
what can epithelial cells produce
enzymes
hormones
lubricating fluids
how does mucus prevent microbes entering the body
traps dirt and germs and prevents them entering into the blood
what do ciliated epithelial cells in the respiratory system do
sweep away mucus and trapped microbes away from the lungs
other first line defences include
tiny hairs in nose
wax in ears
coughs and sneezes
tears containing lysozymes
friendly bacteria preventing bad bacteria
what is a pathogen
an organism that can cause disease
what is released if something breaks through the skin
histamine
what is histamine released from
mast cells
what is the inflammatory response
histamine released from mast cells
vasodilation
increased capillary permeability
what are the cell signalling proteins
cytokines
what is an antigen
a protein located embedded into the surface of cells
what is the non specific blood cell
phagocyte
what process do phagocytes undergo
phagocytosis
what is phagocytosis
the phagocyte engulfs the pathogen and lysosomes (containing digestive enzymes) fuse with the vacuole and digest the pathogen
