lymphocytes: white blood cells that help the body fight pathogens b cell: white blood cell that...
TRANSCRIPT
IMMUNE SYSTEMPROTECTION 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
Cycle of fighting a pathogen
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
IMMUNITY 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
PATHOGENS
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
HOW PATHOGENS ARE SPREAD
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