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=MODULE 2.5= =I. Topic Title:=

THE IMMUNE SYSTEM

=II. Topic Description:=

The biological system involved in the body's defenses against foreign materials. This will discuss the two types of immune responses: humoral-mediated and cell-meadiated. This will also touch on some autoimmune diseases which is of particular importance to humans.

=III. Terminal Objectives:=

At the end of the lesson, the students should be able to: 1. Explain the functions of the immune system. 2. Enumerate and differentiate the components of the immune system. 3. Relate the immune system with the circulatory system. 4. Be aware of the latest researches and issues related to the immune system.

=IV. Content Presentation:=

THE IMMUNE SYSTEM

The body has two main lines of defense agains invaders: nonspecific defenses resist all infections in a stereotyped manner; specific defenses like the immune system recognize and fight each invader individually. Human immunodificiency virus (HIV), which produces AIDS, infect cells of the immune system, eventually destroying the body's ability to fight other infectious agents and cancer.

The Immune System is made up of lymphocytes and other cells associated with them. The lymphocytes patrol the body monitoring the nature of the molecules expressed on the surface of all its cells. Most of our lymphocytes fall into two major categories: T lymphocytes and B lymphocytes. Both the T and B cells are produced from the bone marrow, T cells, though, migrate to the thymus while B cells become mature in the bone marrow, leaving when they become active in immunity.

One of the major tasks of the immune system is to mount a defense against foreighn materials, called antigens that enter the body. __[|Cell-mediated immune responses],__ uses T cells. When T cells recognize a particular antigen, they proceed to recruit a variety of other cells (e.g. macrophages) to take action to destroy the antigen. Antibody production, known as the __[|Humoral-mediated immune response]__, is the responsibility of the B cells. However, B cells also need the asistance of T cells, called helper T cells, which enable the B cells specific for the antigen to proliferate and develop into plasma cells. Plasma cells are the cells that actually secrete antibodies.

Immunity is the state of enhanced responsiveness to a particular molecular shape (epitope), as would be present on an invading bacterium, induced by prior contact with that epitope. There are two types of immunity: active and passive. Active immunity involves the actual production of antibodies by the individua's own immune system, whereas in passive immunity the antibodies have not been made by the individual's own immune system.

The immune system sometimes fails. In autoimmune diseases, the system turns against the body's own molecules. In immunodificiency diseases, immune components are lacking and infections recur. Physical and emotuional stress may weaken the immune system. Allergies are abnormal sensitivities to antigens (allergens) in the surrounding. The __[|AIDS]__ virus attacks helper T cells, crippling both humoral and cell-mediated immunity. So far, AIDS is incurable, but drugs and vaccines offer hope for the future.l

=V. Activities:=

IMMUNE SYSTEM

Look for a journal article on any of the cells of the immune system and do a powerpoint presentation of the article in class. Take note of the following: background on the cell (development, function, morphology) then discuss the journal article - give the title, author, objective, methodology, results, summarize discussion and conclusion, then give your opinion on it. Research paper: submit the journal article, a report on the powerpoint presentation including reactions and recommendations generated from the presentation. = = =VI. References:=

1. BOOKS: Campbell, Neil A. 1996. Biology. 4th ed. California: The Benjamin/Cummings Publishing Company, Inc. Campbell, N.A., Mitchell, L.G. & Reece, J.B. 2003. BIOLOGY: Concepts and Connections. 4th ed. California: Addison Wesley Longman, Inc De la Paz, R.M., Amparado, E.A., & De Jesus, J.B. 1998. Essentials of Biology. Quezon City: ACLC Trading Enterprises. Gartner, L.P & Hiatt, J.L. 2001. 2nd ed. Color Textbook of Histology. Pennsylvania: WB Saunders Company. Kimball, J.W. 1994. 6th ed. Biology. U.S.A.: Wm. C. Brown Publishers.

2. URL: http://www.umm.edu/ency/article/000821.htm http://www.immunecentral.com/diseases/aids.cfm

=VII. Assessment:=

Test yourself [|here].

=VIII. Disclaimer and Copyright Notice=

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=IX. Topic Writer:=

X. Document History:
Version 1.0 - Date: 14 Nov 2006 Revision 1.0 -Date: