Sho Mula

Name Rodrigo Bran Peña Class 5 Bach Date 5/9/2012


35.4 Immune System Disorders
Lesson Objectives
Explain what happens when the immune system overreacts to harmless pathogens.
Describe how HIV is transmitted and how it affects the immune system.
Lesson Summary
When the Immune System “Misfires” Sometimes, the immune system overreacts to otherwise harmless antigens. Threetypes of disorders are caused in this way.
The most common immune-system disorders are allergies, which occur when antigens enter the body and bind to mast cells. The mast cells release histamines, which increase the flow of blood and fluids to the area. This causes allergy symptoms.
Allergic reactions in the respiratory system can cause asthma, a dangerous chronic disease in which the airpassages narrow and breathing becomes difficult.
When the immune system makes a mistake and attacks the body’s own cells, an autoimmune disease results. Autoimmune diseases include Type I diabetes, rheumatoid arthritis, and lupus.

HIV and AIDS In the 1970s, clusters of cases of opportunistic diseases—diseases that attack people with weakened immune systems—led to the discovery of a new diseasecalled acquired immunodeficiency syndrome (AIDS).
Research revealed that AIDS is an infectious disease caused by human immunodeficiency virus (HIV). HIV attaches to receptors on helper T cells. Once inside the cells, HIV copies itself and the new viruses infect more helper T cells.
HIV infection gradually leads to the death of more and more T cells. When a person’s T cell count drops to aboutone-sixth the normal level, the person has AIDS.
HIV can only be transmitted through contact with infected blood, semen, vaginal secretions, or breast milk.

When the Immune System “Misfires”
For Questions 1–5, complete each statement by writing the correct word or words.
1. An overreaction of the immune system to antigens of pollen and other harmless substances is called a(n) Allergies.
2.Sneezing, a runny nose, and watery eyes are symptoms of the Inflammatory response in the respiratory system.
3. Drugs called Antihistamines counteract the effects of Histamines produced by mast cells.
4. A dangerous condition that affects the respiratory system and can be caused by allergies is called Asthma.
5. Examples of Attacks can be triggers for allergic reactions include tobaccosmoke, pollution, molds, and pet dander.
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6. What is an autoimmune disease?
When the immune system attacks the body´s own cells, it produces an autoimmune disease.

7. Describe the advantage and disadvantage of treating an autoimmune illness such as lupus.
The disadvantage is that antibodies attack organs and tissues causing areas of chronic inflammationthroughout the body. The advantage is that some autoimmune diseases can be treated with medications that alleviate specific symptoms.


8. Complete the table about autoimmune diseases.

Autoimmune Diseases |
Autoimmune Disease | Organ or Tissue That Is Attacked |
Type I diabetes | Antibodies attack insulin-producing cell in the pancreas. |
Rheumatoid arthritis | Connectivetissues around the joints |
Lupus | Causing areas of chronic inflammation throughout the body. |

HIV and AIDS
9. What does AIDS stand for?
Acquired immunodeficiency syndrome.
10. What is the term that describes diseases that attack people with a weakened immune system?
AIDS.
11. List four body fluids that can transmit AIDS.
A. Blood.
B. Breast milk.
C. Semen.
D. Vaginalinfection.
12. What behaviors prevent people from being infected with HIV?
The only no-risk behavior with respect to HIV transmission is abstinence from sexual activity and intravenous drug use.

13. Why is curing HIV infection so challenging? Explain your answer.
Because, no one has develop a vaccine that offers protection for any length of time.



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