Bodily Defenses Image Map


Activity #2: Worksheet for Bodily Defenses

This activity is the worksheet for bodily defenses.

Student Q/A Response Sheet for Activity #2
(right mouse click and select "open in a new window" to open as a MS Word document for printing).

Worksheet 1 – Bodily Defenses

1. Why must our body have defense mechanisms? What are the defense mechanisms of the body and how do they work?


2. Draw a cross-sectional picture of your skin and label the key parts. How is your skin a barrier.

The Immune System

3. The "defenders" of the immune system are _______________________. They are rushed to the site of a wound or injury through the ________________. The _______________________ become concentrated in the injured area to stop _______________ from entering and damaging surrounding tissues.

4. Describe what a vaccine is and what it is meant to do.

5. Make a drawing of a white blood cell binding an antigen, then releasing an antibody, and then draw the interaction between the antigen that triggered its production. Make a drawing that shows the difference from the antibody’s reaction with OTHER antigens.

6. Compare and contrast, using a Venn diagram, to show the differences in natural immunity and acquired immunity and what they have in common.

Recall that there are really 2 types of lymphocytes, B-cells and T-cells.  The B-type makes circulating antibodies. The B-type is made in lymph nodes and bone marrow. The T-type lymphocyte kills foreign cells on contact or helps by releasing chemicals that assist in killing invaders. T-cells recognize the surface proteins on other cells and when they come in contact with an intruder, the invading cells are killed. These lymphocytes are made in a gland at the base of the neck, called the thymus. Production of T-cells can be reactivated at any time, if a foreign antigen is presented. T-cells also play a role in the rejection of transplanted tissue and in fighting cancer.

7. Why would the body not be adequately protected if it only had the B or T-cell immune system? Why does it need BOTH types of immune responses?

In addition to the body's natural defenses, vaccines may be administered to boost the body's immunity and prevent disease. For many diseases, the vaccine contains the infection, but it is weakened. The goal in vaccine manufacturing is to make the infectious organism weak enough so that it won't cause the disease but strong enough so that it will activate the body's immune system.
Once the immune system is activated by the disease agent, antibodies are created to fight the disease. The antibodies are "programmed" specifically to fight that particular infectious agent. The original antibodies that are generated in response to a vaccination eventually go away, but the immune system has a "memory".
After a vaccination, if the disease agent that was vaccinated against enters the body, new antibodies are immediately created using the "programming" from the old vaccine. The new antibodies are specifically developed to destroy the specific disease agent that has entered the body.

8. Make a list of diseases for which there are vaccines. Make one list for humans and one for animals. Make another list of diseases for which there are NO vaccines, categorizing the list, once again, by human and animal diseases.

9. Research some of the human vaccines you have listed. Indicate how often the vaccination has to be repeated and any other interesting information you find out about different vaccines. Be sure to write down the websites or books you use to find your information (your sources).

10. State the two types of white blood cells and explain the functions of each.


11. Draw a concept map of how your body’s defense mechanisms attack bacteria and viruses.


Special Hazards


As you may recall from the "Common Hazards" section of our unit, sunburn results when the amount of exposure to the sun or other UV light source exceeds the ability of the body's protective pigment, melanin, to protect the skin. Fair-skinned people with light-colored hair are at greatest risk of sunburn because their bodies produce lower amounts of melanin. While dark skin has more natural protection from the sun, it, too, can burn. Considering this information, answer the following using your Q/A Response Sheet and other resources if you have access to them:

1. Radiation from the UV light (sunlight) has to hit something in order for it to dissipate its energy. Melanin provides molecules that safely absorb radiation energy. How does this protect the tissues of your body and your skin?

2. When you sit outside for too long, you get sunburned. What is happening underneath the surface of the skin to allow the sunburn to occur?

3. When you go into a swimming pool, do you see the burn immediately or after a few hours? Why do you think this is so?

4. What time of the day is most dangerous when it comes to sunburn?

5. The most common form of skin cancer is the most dangerous, melanoma. The word "melanoma" means that melanin in the body has become cancerous. Why do you think that these cells are more prone to cancer?

6. What is the best way to prevent sunburn that could develop into skin cancer?

7. What SPF sunscreen would you need to stay in the sun for 200 minutes if you are normally okay in the sun for 5 or 6 minutes?

8. What percentage of melanin do you think can be found in the skin of an American Indian? What is different about their pigmentation that causes their skin to have a distinctive coloring?


As you've read in "Common Hazards," AIDS stands for "Acquired Immune Deficiency Syndrome": Acquired means you can catch it; Immune Deficiency means a weakness in the body's system that fights diseases. Syndrome means a group of health problems that make up a disease.

AIDS is caused by a virus called HIV: Human Immunodeficiency Virus. When you get a blood test for HIV, the test is really for antibodies. If you have them in your blood, it means that you have HIV infection. People who have the HIV antibodies are called "HIV-Positive".

Being HIV-positive, or having HIV disease, is not the same as having AIDS. Many people are HIV-positive but don't get sick for many years. As HIV disease continues, it slowly wears down the immune system. Viruses, parasites, fungi and bacteria that usually don't cause any problems can make you very sick if your immune system is damaged. These are called " opportunistic infections".

Answer the following using information from this unit, other web-based resources, or printed sources:

1. List some problems a person might have with an immune system that is malfunctioning.

2. When testing for the HIV virus, health care workers look for the presence of HIV antibodies. Why would this be an excellent indicator that the virus exists in the body?

3. Would there be any limit to the types of diseases that could be considered opportunistic? How would bacterial infections effect someone with AIDS? What about viruses? Why do you think diseases that effect AIDS patients are called "opportunistic"?

4. Sometimes AIDS patients are told that they are in remission of the AIDS disease. Does this mean that they are cured? What do they mean by "remission"?

Activity 2

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