Download Immune system protection inside the body






Lymphocytes: white blood cells that
help the body fight pathogens
B cell: white blood cell that produces
antibodies
Helper T cell: WBC that signals B cells
to produce antibodies
Antibody: special protein that helps
fight infection
Macrophage: WBC that surrounds and
destroys pathogens

Pathogen invades body  helper T cells
send signals to B cells  produces
antibodies 
B cells enter the lymph nodes and
lymph tissues antibodies travel
through the blood to destroy
pathogen destroyed pathogens enter
lymph, filtered in lymph nodes, and
removed by spleen




The body’s resistance to disease-causing
agents
Active immunity: resistance to disease
due to the presence of antibodies
Vaccine: substance containing dead or
weakened pathogens
Passive immunity: results from
introducing antibodies into a person’s
bloodstream; short-term and used when
risk of developing disease in immediate




A germ that causes disease
Communicable disease or infectious disease:
illness caused by pathogens that can be
spread from one living thing to another
Bacteria: single celled microorganism; can be
beneficial; those that are harmful cause
disease by releasing toxins into the body
Fungi: single and multi celled parasitic
organisms; obtain their food from organic
materials


Viruses: one of smallest known pathogens;
takes over the cell and causes it tomake
more viruses; newly produced viruses are
released and take over other cells
Protozoa: tiny, single-celled organisms that
produce toxins that cause disease





Direct contact
Through the air
Contact with contaminated objects
Handling or being bitten by an insect
or animal carrying the pathogen
Contact with contaminated food and
water