1. Name the two major functions of the immune system:
• __ To destroy disease-causing organisms_____________
• _______ To detect and kill abnormal cells such as cancerous cells________________
2. Pathogens are classified according to their size and where they are located in the body. List the five types of pathogens from largest to smallest:
• _____ Parasitic worms_____
3. Which type of pathogen is always intracellular? ______Viruses__________ Which type of pathogen is always extracellular? _______Parasitic worms_________
4–5. Name the three main lines of defense and give an example of each:
Line of defense
6. When the surface barriers (innate external defenses) are penetrated, what is the next line of defense? ___ Innate internal defenses
7. This defense mechanism (named in question 6) identifies enemies by recognizing ____markers_____ unique to the pathogens. When they are overwhelmed, they secrete ______chemical messengers____ to mobilize the adaptive defenses.
8. Name the four key ways adaptive defenses differ from innate defenses:
• ______are specific________________
• ___involve B and T lymphocytes_________
• __have memory_____________
• __are systemic______________
9. B and T lymphocytes recognize pathogens by binding to them. What the lymphocyte recognizes is called the _____antigenic deteminant_____________ found on the antigen.
10. Specific B cells called ___plasma______ cells secrete __antibodies____________, which bind to the antigens.
Humoral Versus Cellular Immunity
11. ____Humoral________ immunity is directed against pathogens in the extracellular fluid. This immunity involves __B_ lymphocytes.
12. ________Cellular____ immunity is directed against pathogens within the cells. This immunity involves __T_ lymphocytes.
13. Which type of immunity