Your Bodys Lines of Defense What are the 3 lines of defense your body has to fight pathogens? a. Barriers to pathogens b. the Inflammatory Response c. the Immune Response
1 st Line of Defense How does your skin keep pathogens from getting in? Chemicals in the oil and sweat in your skin can kill pathogens. Pathogens can fall off when dead skin falls off. Dead skin cells are packed together tightly, preventing pathogens from getting in.
1 st Line of Defense How do your breathing passages keep pathogens from getting in? Pathogens are trapped and removed in the mucus and cilia of your nose, pharynx, trachea, and bronchi. Pathogens can irritate you and cause you to sneeze or cough, which forces the pathogens out.
1 st Line of Defense How does your mouth and stomach keep microbes from getting in? Saliva in your mouth contains chemicals that destroy pathogens. Stomach acid destroys pathogens.
1 st Line of Defense YOUR BODYS 1 st LINE OF DEFENSE: –Skin –Breathing Passages –Mouth & Stomach These barriers work really well, but sometimes pathogens can still get in….
2 nd Line of Defense When pathogens get past your first line of defense, and begin to damage cells. The cells release chemicals that begin the 2 nd line of defense: THE INFLAMMATORY RESPONSE.
2 nd Line of Defense What is the Inflammatory Response? Fluid and white blood cells leak from blood vessels into nearby tissues. The white blood cells fight the pathogens. This is the bodys general defense (used against everything).
2 nd Line of Defense What is a Phagocyte? What kind of cell is it? A phagocyte is a type of white blood cell that engulfs pathogens and destroys them by breaking them down. It doesnt care what kind of pathogen it is, it still tries to kill it.
A Phagocyte destroying bacteria
2 nd Line of Defense What happens during inflammation? The area around the damaged cells swells up because more blood flows to the area and more white blood vessels are present. This makes the area look red, swollen, and feel warm.
2 nd Line of Defense Why do we get a fever? Sometimes during the inflammatory response, chemicals are produced. They raise the temperature of your body because it slows the growth and reproduction of bacteria. ITS A GOOD THING.
3 rd Line of Defense If the infection from the microbe is bad enough to cause a fever, it triggers the 3 rd line of defense – the IMMUNE RESPONSE.
3 rd Line of Defense What are Lymphocytes? A type of white blood cell that distinguishes between the different kinds of pathogens. There are 2 major kinds – T cells and B cells.
3 rd Line of Defense What do T Cells do? T cells identify the type of pathogens that are infecting you.
3 rd Line of Defense What are Antigens? Antigens are molecules found on each pathogen. They tell your immune system whether the pathogen is part of your body or foreign.
3 rd Line of Defense What do B Cells do? B cells produce proteins called antibodies that help destroy pathogens.
3 rd Line of Defense What are Antibodies? Antibodies are proteins that help kill pathogens. They attach to antigens like 2 puzzle pieces. Once theyre attached, they mark the pathogen for death by: Making the pathogen clump together, or preventing the microbe from attaching to your cells, or making it easier for phagocytes to kill the pathogen.