1. Topic-
The Excretory System
2. Content-
Definition of excretion. Parts of the excretory system. The Kidney.
3. Goals: Aims/Outcomes-
To understand the excretory system and it's functions.

4. Objectives-
At the end of the lesson, the student should be able to:
1. Explain in his own words what excretion is.
2. Identify the parts of the excretory system.
3. To discuss the different parts of the kidney as well as its functions.
5. Materials and Aids-
1.Visual aid on Excretory system.
2.Otto, J.H. and Towle, A. Modern Biology
6. Procedures/Methods-

A. Introduction-

Teacher: Good morning students. I am Ms. Smith. I will be your teacher today.
Teacher: Who among you frequently asks permission to have a bathroom break?
How many times do you urinate in a day? Ok so today, our lesson will be on the excretory system, it's parts and functions.

B. Development-

Teacher: Today, our lesson is on the excretory system.
How many of you know what excretion is? ...
Teacher: What is excretion?
Possible answers:
*excretion is the process by which the body gets rid of wastes.
Teacher: Wastes come from proteins. These proteins are broken down to amino acids and the nitrogen-contaning parts are released as waste in the form of urea and uric acid.
Build up of wastes in the tissues will interfere with cell functions and poison the cells. It may cause fever, convulsions, coma and even death. In humans, the cell discharges its waste materials into the tissue fluid. From there, the waste enter into the blood stream. The blood carries them to excretory organs to be eliminated.
2. The excretory system and it's functions.
Possible answers:
* The excretory system is a passive biological system that removes excess, unnecessary or dangerous materials from an organism, so as to help maintain homeostasis within the organism and prevent damage to the body. It is responsible for the elimination of the waste products of metabolism as well as other liquid and gaseous wastes.
**Present the excretory system visual aid to the class
Teacher: What are the parts of the excretory system?

1.kidneys - main excretory organs, it is reddish brown, bean-shaped is about the size of your fist. (Call a volunteer to point out the location of the kidney). Kidneys are sophisticated reprocessing machines. Every day, a person's kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.

2.ureter - a long narrow tube leading from each kidney. They are muscular ducts that propel urine from the kidneys to the urinary bladder. In the adult, the ureters are usually 25-30 cm (10- 12 in) long

3.urinary bladder - where the ureter empties and where urine is stored, collects urine excreted by the kidneys prior to disposal by urination

4.urethra - where urine exits the body

Parts of the kidney:
1.cortex - firm outer part of the kidney, makes up 1/3 of the kidney tissue
2.medulla - inner 2/3 of the kidney tissue
3.pyramids - cone shaped projections in the medulla
4.pelvis - funnel shaped structure leading to the ureter
5.nephrons - units of the kidney that control the chemical make up of blood.


Who would like to come to the board and point a part or identify a part of the excretory system. Point the part and tell us what it is. Who would like to point another part?

Checking for understanding-

Group yourselves into 8. Group activity, draw the excretory system and its parts.


Teacher: Who can summarize what we have learned today?...Thank you and I hope to see you again tomorrow. Have a good day.
7. Evaluation-
Why is the excretory system important?

This Lesson Plan is available at (www.teacherjet.com)