By the end of the lesson you should be able to
Outline the stages in phagocytosis.
Describe how antibodies work and how they are specific.
skin prevents entry
tears antibacterial enzymes
saliva antibacterial enzymes
stomach acid low pH kills harmful microbes
mucus linings traps dirt and microbes
“good” gut bacteria out compete bad
= disease causing micro-organisms
Involves white blood cells
invading pathogens are targeted by macrophages
lymphocytes produce chemicals called antibodies that target specific pathogens
Monocytes and macrophages
Provide a non-specific response to infection
Stages in phagocytosis
Phagocyte detects chemicals released by a foreign intruder (e.g. bacteria)
Phagocyte moves up the concentration gradient towards the intruder
The phagocyte adheres to the foreign cell and engulfs it in a vacuole by an infolding of the cell membrane.
Lysosomes (organelles which are rich in digestive enzymes & found in the phagocytes cytoplasm) fuse with the vacuole & release their contents into it.
The bacterium is digested by the enzymes, and the breakdown products are absorbed by the phagocyte.
During infection, hundreds of phagocytes are needed.
Pus is dead bacteria and phagocytes!
link to phagocytosis
An accumulation of : -
Provide a specific immune response to