Exercises: The Immune System and Body Defenses

Skin, mucus in the airways and stomach acid are often called the body's first line of defense. Classify these three structures as part of the innate or the adaptive immune response, and state in one sentence what they have in common in how they protect the body.

Define the term antibody. In your definition, name the type of white blood cell that produces antibodies and explain what an antibody binds to.

Emma cut her knee during a soccer game. Within an hour, the area was red, warm and slightly swollen. Name this innate response and state one benefit it provides to the body.

Compare the innate immune response with the adaptive immune response. Your answer should address (a) how fast each begins, (b) whether each is specific to one pathogen, and (c) whether each produces memory.

A flu virus spreads through a middle school during winter. Jayden's classmate coughs without covering her mouth, and Jayden later touches a doorknob and then rubs his eyes. Describe two different ways the virus could move from person to person in this scenario. Then explain why a virus needs a host cell in order to reproduce.

The table shows the concentration of antibodies against a pathogen in a patient's blood after two exposures.

(a) Describe how the response after the second exposure differs from the response after the first. (b) Explain, using the role of memory cells, why this difference occurs.

Mateo steps on a rusty nail and develops a deep puncture wound. Analyze how at least three body systems (for example, integumentary, circulatory, immune, and nervous) interact to detect the injury, limit infection and begin repair. In your answer, identify which steps are part of the innate response and which are part of the adaptive response, and explain why the adaptive response would take longer to reach full strength.

A vaccine contains a weakened or inactivated form of a virus. A student argues: "A vaccine protects you because it kills the virus inside your body." Evaluate this claim. In your answer, (a) explain what actually happens in the body after vaccination, (b) describe why a vaccinated person who later meets the real virus often has a milder illness or none at all, and (c) explain why a vaccine against a virus that mutates quickly may need to be updated.