m2t04

=MODULE 2.4= =I. Topic Title:=

THE CIRCULATORY SYSTEM

=II. Topic Description:=

The biological system involved in the transport of molecules in living organisms. These molecules includes nutrients, wastes, hormones and the respiratory gases. This will also describe the components and pathways of the system. A brief discussion of cardiovascular diseases will also be taken up.

=III. Terminal Objectives:=

At the end of the lesson, the student should be able to:

1. Explain the function of the circulatory and immune system. 2. Enumerate and identify the different components of the circulatory system. 3. Define the function of the various parts of the circulatory system. 4. Relate the circulatory and immune system to each other

IV. Content Presentation:

THE CIRCULATORY SYSTEM

The Circulatory System is made up of blood (RBC, WBC and Platelets), blood vessels (arteries, veins and capillaries), and the heart, which forces blood through the vessels. All the blood ccells are suspended in a fluid called plasma. The role of the RBC is to transport oxygen and carbon dioxide. Each of the WBC participates in defending the body against pathogens while the platelets is involve in the blood clotting mechanism.

All the functions of the blood takes place in the capillary beds. The other two blood vessels are the __[|arteries]__ - which carries blood away from the heart, and the veins - which carries blood towards the heart. Aside from blood, interstitial fluid, which leaks from the capillaries, bathes the cells in its vicinity, supplying them with the molecules they need and removing their wastes and seceretions. Most of the interstitial fluid returns directly to the capillaries. The remainder enters the __[|lymphatic system]__ but is essentially returned to the blood at the subclavian veins. The __[|lymphatic system]__ is also involved in the immune response system

The __[|heart]__ is a pumping organ. In mammals and birds, there are actually two pumps: one for forcing blood through the pulmonary (lung) vessels and the other for forcing blood through the vessels of the systemic (body) circulation. The human heart has four chambers: right atria, right ventricle, left atria and left ventricle.

The electrical activity that causes the __[|heartbeat]__ is intrinsic to it. However, the rate of beating is controlled by the nervous system. The pressure of the blood in the major arteries rises and falls between a maximum at systole and a minimum at diastole. Blood pressure can be measured using an instrument called the sphygmomanometer.

Understanding the workings of the heart and its related structures will prevent many diseases associated with this system, considering that cardiovascular diseases, particularly __[|atheroscelorosis]__ is currently the number one cause of deaths in humans.

V. Activities:

1. Make a table comparing the various circulatory systems of the different animal species, vertebrates and invertebrates. Construct this on a 1/2 size illustration board and develop it into a poster.

2. Fun games with the circulatory system. Access http:/tgfl.skoool.co.uk LEARN Path lessons in Biology.

=VI. References:=

1. BOOKS Campbell, Neil A. 1996. Biology. 4th ed. Calfornia: 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. Color Textbook of Histology. 2nd ed. Pennysylvania: WB Saunders Company Kimball, J.W. 1994. Biology. 6th ed. U.S.A.: Wm. C Brown Publishers 2. URL http://sin2.fi.edu/biosci/vessels/arteries.html http://www.stjohnsmary.org/healthinfo/adult/cardiac/arteries.asp http://www,innerbody.com/image/lympov.html http://www.jdaross.cwc.net/lymphatic_system.html http://www.acm.uivc.edu/sigbio/project/updated-lymphatic/lymph 1.html

=VII. Assessment:=

Test yourself [|here] = = =VIII. Disclaimer and Copyright Notice=

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=IX. Topic Writer:= Murita Antonia S. Panganiban, maspanganiban@gmail.com, maspanganiban.wikispaces.com

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