Review your knowledge of infection and immunity by answering the questions below. Refer to your textbook if necessary.

1. List and describe three of the body's physical or chemical barriers against infection.
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2. What general type of cells carry out the immune response?
   
   
   Where are these immune defenders produced?
   
   
   Describe each of the following types of cells and explain their role in the immune response.
   
   Neutrophils
   
   
   Macrophages
   
   
   Natural killer cells
   
   
   Dendritic cells
   
   
   Helper T cells
   
   
   
   Killer T cells
   
   
   Suppressor T cells
   
   
   B cells
   
   
   Memory T and B cells
   
   
   
3. What are antibodies? What is their role in the immune response?
   
   
   
4. How do the body's defenders recognize an enemy? What is an antigen?
   
   
   
5. What is the inflammatory response?
   
   
   
6. Briefly describe the four phases of the immune response.
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7. What is immunity? When and how does it occur?
   
   
   
8. When is an infected person contagious?
   
   
   
9. What is a vaccine?
   
   
   What are the two types of immunity that a vaccine can confer?
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10. What is an allergic reaction and how does it occur?