Defence Against Diseases
Microorganism - Bacteria, Viruses, Fungi
Not all cause disease. Microbes which do are called pathogens
Bacteria - These produce toxins (poisons) which harm the body and make you ill.
Viruses - These are much smaller than bacteria and infect the body cell and reproduce inside it. This causes the body cell to break and this damage causes an illness.
Antigens - A protein specific to the pathogen which are on the pathogen's surface
Whit Blood Cells
They work in three ways:
Ingest - the cell engulfs and ingests it. The pathogen is then digested by enzymes released whilst inside the cell.
Produce antibodies - The white blood cells produce antibodies which are the right size to attach to the antigens on the pathogens to make it harmless. Producing antibodies which are the right size can take a while to produce.
Produces antitoxins - Antitoxins produced deactivate the toxins produced by the pathogen to prevent…