3rd Line of Defense Flashcards
THIRD LINE OF DEFENSE
If a pathogen infection is severe enough to cause a fever, it also triggers the THIRD LINE OF DEFENSE—the immune response
immune response
The immune response is controlled by the immune system, your body’s disease fighting system.
What can the cells of the immune system do?
The cells of the immune system can distinguish between different kinds of pathogens
Immune system cells
The immune-system cells react to each kind of pathogen with a defense targeted specifically at that pathogen.
Which immune system cells react to each kind of pathogen with a defense targeted specifically at that pathogen.
white blood cells
What are the white blood cells that do this called?
lymphocytes
what are lymphocytes
a form of small leucocyte (white blood cell) with a single round nucleus, occurring especially in the lymphatic system.
What are the 2 major kinds of lymphocytes?
T lymphocytes and B lymphocytes, which are also called T cells and B cells.
T Cells facts
The T cells are like soldiers who search out and destroy the targeted invaders.
o A major function of T cells is to identify pathogens and distinguish one kind of pathogen from another.
o You have tens of millions of T cells circulating in your blood. Each kind of T cell recognizes a different kind of pathogen.
o What T cells actually recognize are marker molecules, called antigens, found on each pathogen. Antigens are molecules on cells that the immune
system recognizes either as part of your body or as coming from outside your body.
o All cells have antigens, and each person’s antigens are different from those of all other people
o Each different pathogen has its own kind of antigen. Antigens differ from one another because each kind of antigen has a different chemical structure
Antigens
Antigens are molecules on cells that the immune system recognizes either as part of your body or as coming from outside your body.
B Cells
B cells produce chemicals that help destroy each kind of pathogen. These chemicals are called antibodies.
antibodies. (B cells facts)
o Antibodies lock onto antigens. Each kind of B cell produces only one kind of antibody. Each kind of antibody has a different structure.
o Antigen and antibody molecules fit together, like pieces of a puzzle. An antigen on a flu virus will only bind to one kind of antibody—the antibody that acts against that flu virus
o When antibodies bind to the antigens on a pathogen, they mark the pathogen for destruction.
o Some antibodies make pathogens clump together. Others keep pathogens from attaching to the body cells that they might damage.
o And finally other antibodies make it easier for phagocytes to destroy the pathogens