Body Defenses: Nonspecific DESCRIBE PATHOGENS!!

Think, pair, share What parts of your body help you keep germs out? Can you think of any body processes that help fight germs and disease?

Challenge Problem turn in the African Illness packet to the front What is happening here? Make an explanation the best you can.

Trypanosomiasis African Sleeping Sickness 1. Virus, Bacteria, Protozoan, Other? 2. How is it transmitted? 3. How does the body react to the infection? 4. Can we fight it without drugs? 5. You cannot turn in your packet at lunch without using a computer. You must turn in your own

Body Defenses The body is constantly in contact with bacteria, fungi, and viruses The body has two defense systems for foreign materials 1) Nonspecific defense system Mechanisms protect against a variety of invaders Responds immediately to protect body from foreign materials Slide 12.15a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Body Defenses 2) Specific defense system Specific defense is required for each type of invader Also known as the immune system Slide 12.15b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz Explain the difference between non-specific and specific body defenses.

Nonspecific Body Defenses Body surface coverings Intact skin Mucous membranes Specialized human cells Chemicals produced by the body Slide 12.16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

First Line of Defense

Surface Membrane Barriers The skin Physical barrier to foreign materials pH of the skin is acidic to inhibit bacterial growth Sebum (sweat) is toxic to bacteria Vaginal secretions are very acidic Slide 12.17a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Surface Membrane Barriers Stomach mucosa Secretes hydrochloric acid Has protein-digesting enzymes Saliva and lacrimal fluid contain lysozyme Mucus traps microogranisms in digestive and respiratory pathways Slide 12.17b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz Which of the First Line of Defenses do you think is the most important any why?

Second Line of Defense

Defensive Cells Phagocytes (neutrophils and macrophages) Engulfs foreign material into a vacuole Enzymes from lysosomes digest the material Slide 12.18a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.6b

Defensive Cells Natural killer cells Can lyse and kill cancer cells Can destroy virus- infected cells Slide 12.18b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 12.6b

Inflammatory Response Triggered when body tissues are injured Produces four cardinal signs Redness Heat Swelling (from increased blood flow and white blood cells in the damaged region) Pain Results in a chain of events leading to protection and healing Slide 12.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functions of the Inflammatory Response Prevents spread of damaging agents Disposes of cell debris and pathogens Sets the stage for repair Slide 12.20 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Steps in the Inflammatory Response Figure 12.7 Slide 12.21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Antimicrobial Chemicals Damage foreign cell surfaces Attract neutrophils and macrophages Has vasodilators, chemotaxis, and opsonization Figure 12.8 Slide 12.22b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Antimicrobial Chemicals Interferon Proteins secreted by cells that have been infected with a virus The proteins bind to healthy cell surfaces to inhibit viruses binding to more cells Slide 12.22c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Fever Abnormally high body temperature Hypothalmus heat regulation can be reset by pyrogens (secreted by white blood cells) High temperatures inhibit the release of iron and zinc from liver and spleen needed by bacteria Fever also increases the speed of tissue repair Slide 12.23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz When a patient has broken a bone and the area becomes inflamed, what purpose does that serve? Why do kids have 103F temperature when they have an ear infection?    

Non-specific Comic Strip Create 2 comic strips modeling the non-specific defenses against pathogens. One will be an example of the First Line of Defense (outside) One will be an example of the Second Line of Defense (inside) Minimum 3 panes each, probably need more Use color Use captions to help with content Pretend your grandma is coming over for dinner and she has to able to understand the cartoons.

Example First line of defense - -? Second line of defense Bacteria gets on skin No cuts, bacteria sits on skin and gets washed in sweat Bacteria hates sweat! Dead bacteria Sadface bacteria, happyface human Second line of defense Finger gets splinter Bacteria gets under skin Body sends gangsta macrophages in army hats to fight bacteria Gangsta macrophages are victorious!!