m2t07

=MODULE 2.7= =I. Topic Title:=

=__**EXCRETORY SYSTEM**__=

=II. Topic Description:=

The Excretory system is responsible for the elimination of wastes produced by homeostasis.The word excretion means the removal of waste substances from the body. Several organs are involved with the excretory system, including the kidneys, sweat glands, lungs. and rectum, The primary organs of excretions, however, are the kidneys. Excretion is essential to the health of the body because the wastes are poisonous. If the wastes build up and are not eliminated, they can cause serious problems even death. Carbon dioxide and water vapor are released by the lungs. Other waste materials, such as urea, uric acid, salts and nitrogenous wastes, are removed by the kidneys and sweat glands.

=III. Terminal Objectives:=
 * 1) To clearly define the word excretion.
 * 2) To describe the function of the skin, kidneys, lungs and liver in the excretory process.
 * 3) To identify the structure and function of the kidney and its parts.
 * 4) To explain how the nephron works.
 * 5) To identify and explain the difference between filtration and reabsorption.

IV. Content Presentation:
Every human has two bean shaped kidneys. Each kidney is made up of three sections: the renal cortex, the renal medulla, and the renal pelvis. The blood arrives at the kidney via the renal artery, which is branching into many afferent arterioles. These arterioles lead to the Bowman's Capsules of nephrons, where the wastes are eliminated by pressure filtration. Peritubular capillaries also surround the nephron so substances can be taken in and out of the blood.

http://www.biologycorner.com/bio3/images/kidney.jpg
 * ORGANS INVOLVED**


 * 1. Kidneys** are bean-shaped organs about 4-5 inches long and composed of one million nephrons each. The kidneys are responsible for the production of urine. Besides the lung, the skin and the intestines, the kidneys are the most important excretory organs within the human body.
 * 2. Ureters** are tubules that connect the kidneys to the urinary bladder.
 * 3. Urinary bladder** acts as temporary storage of the urine.
 * 4. Urethra** serves as passageway of the urine. It is usually regulated by sphincter muscles which regulates urination.

Through the blood, all cell metabolic waste products are transported to the kidneys, where they are then filtered out of the blood plasma and passed out of the body. Excretion takes place through the urine. Urine is produced in the nephrons, of which over a million are to be found in the kidneys. Following several filtrations at different points, the urine eventually leaves the body via the ureter, the bladder and the urethra. The waste products are excreted through the sweat glands in the skin. Water and sodium are the most obvious examples but other substances can be excreted if their normal excretory pathway fails. For example, more urea is excreted by sweat glands when a person has renal failure, unless corrective measures have been instigated. = = = = =V. Activities:= 1. Construct a matrix that depicts the following: - excretion among fishes, mammals, birds, amphibians and reptiles - excretion among protists, poriferans, cnidarians, molluscs, arthropods(crustaceans, insects and arachnids), annelids, nematoda, flatworms, echinoderms.

2. Drink the ff: beverages for 5 days day 1 = nothing but coke day 2 = nothing but iced tea day 3 = nothing but orange juice day 4 = nothing but grape juice day 5 = nothing but water Collect your urine everyday. record the volume and time that you urinate. observe the color and take note of the odor of your urine. record your data and compare the results. Explain the science concepts that are relevant to your results.
 * VI. References:**

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookEXCRET.html http://biology.clc.uc.edu/courses/bio105/kidney.htm http://www.wormatlas.org/handbook/excretory.htm http://www.stclementschool.org/StudentWeb/science/excretionc/excsyst.htm http://www.stclementschool.org/StudentWeb/science/excretionc/excsyst.htm http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20102/Bio%20102%20lectures/Excretory%20System/excretor.htm http://library.thinkquest.org/2824/Excretory.html http://www.edhelper.com/excretory_system.htm http://www.cartage.org.lb/en/themes/Sciences/LifeScience/GeneralBiology/Physiology/ExcretorySystem/HumanExcretory/HumanExcretory.htm http://en.wikipedia.org/wiki/Excretory_system http://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookEXCRET.html http://biology.clc.uc.edu/Courses/bio105/kidney.htm

=VII. Assessment:=

http://school.discovery.com/quizzes35/jorimi/Excretory.html

=VIII. Disclaimer and Copyright Notice= This work is licensed under a [|Creative Commons Attribution-NonCommercial-NoDerivs 2.5 License]

=IX. Topic Writer:= Ms. Joanne R. Miranda jorimi@gmail.com

X. Document History:
Version 1.0 - Date: Revision 1.0 -Date: