human defenxe Flashcards
pathogens
•bacteria and viruses that try to invade our bodies
•this makes us sick
1st line of general defense system consists of
•skin
•blood clotting
•lysozyme
•mucus
•cilia
•stomach acid
skin
•acts as a physical barrier
blood clotting
•repairs damaged skin to prevent entry of pathogens
lysozyme
•enzymes in saliva and tears which kill bacteria
mucus
•traps pathogens
cilia
•tiny hairs in respiratory system that force mucus up into the stomach
stomach acid
•kills bacteria
2nd line of general defense system consists of
•white blood cells
•complement
•interferons
•inflammation
white blood cells
•phagocytes and macrophages
•lots in the lymph nodes, engulf pathogens
complement
•groups of proteins that kill pathogens
interferons
•group of proteins that stop viruses multiplying
inflammation
•damaged cells release chemicals which cause the blood vessels to widen allowing more interferons, complement and white blood cells to flow to the area
where are mucous membrane linings found
•respiratory tract
•digestive tract
•reproductive tract
type of white bloood cell that produced antibodies
•B
helper t cells
•stimulate B cells to multiply
killer t cells
•kill abnormal human cells that are already infected
•use perforin to burst them
suppressor t cells
•stop other immune cells from working properly to prevent an overactive immune response & to stop the immune response when the infection is over
memory t cells
•last for a long time in the body
•they remember a pathogen that has infected the body before and cause memory B cells to be produced
b cells
•mature in the bone marrow
t cells
•mature in the thymus gland
plasma b cells
•produce antibodies
•produce one antibody to one specific antigen
memory b cells
•stay in body for long time after infection
•convert to plasma b cells on reinfection
antigen
•a molecule on surface of pathogen
•indicates the cell is foreign
antibody
•produced in response to antigens to make it easier to see so it can be destroyed
induced immunity
•our ability to resist infection due to the presence of antibodies
passive immunity
•when antibodies are created for us
•these don’t last very long
•eg. breast milk
active immunity
•when our own cells produce the antibodies
•lasts for long time
•eg. flu
artificial immunity
•injections
natural immunity
•breast milk
vaccine
•non lethal dose of a pathogen that triggers antibodies to be produced so they’re ready to fight a real infection
monocytes/macrophages
•kill pathogens displaying antigens
•display this antigen on their cells so antibodies can be produced
where are lymphocytes created
•bone marrow
organs specific to immune system
•thymus
•spleen
•lymph nodes
•tonsils
