LESSON 22 The Systems of the Body: How they Work
Grade Level: 9-10

1. Grades 9-10

2. Overview The body is made up of many parts all of which work together for the common good of the entire body. There are many systems in the body. The composition of a system in the body will determine what functions it performs in the body. Systems in a way are specialised parts of our body. There is however some form of co-ordination of the functions of systems of the body.

3. Purpose The purpose of this lesson is to demonstrate that the body works like a machine. For excellent performance of a machine, the parts must work in unison. Our body then can be perceived as one big machine.

4. Objectives Students will be able to:

i. Define what is a system in our body
ii. Describe how the systems in our body function
iii. Explain why it is necessary for the systems of the body to work in unison.

5. Resources/materials

  • Models of various systems of the body
  • Wall Charts showing labelled systems of the body.

6. Activities and Procedures In Lesson 12, the cell was discussed as the unit of life in a living thing. Human beings start off in life by the joining up of two cells to make one. This single cell then divides over and over again until many millions of cells are made. Thereafter, the cells develop different characteristics. Thus the cells of the body are not all alike. Some do one sort of job and some another. The cells that make up our muscles are not like those that make up our brain.

Cells in our body group themselves together depending on the functions they perform. The cells that do one particular job are grouped together and are called TISSUES. There are many different tissues in the human body. The students should be asked to name some tissues in the body. These may include

  • Muscle tissues
  • Blood tissues
  • Gland tissues
  • Nerve tissues.

A collection of several kinds of tissues make up an ORGAN. Examples of organs are the heart, ears, nose, eyes, stomach and kidneys. The heart for instance is made up of three tissues:

i. Blood tissue,
ii. Muscle tissue and
iii. Nerve tissue.

Every organ has its own special function. The function of the heart is to keep blood flowing round the body by pumping blood into the blood vessel. The teacher should show the students a model of the heart and demonstrate how the heart pumps blood. There is further specialisation in the human body. A collection of organs that perform the same function is called a SYSTEM. There are many systems in the body:

  • Digestive system
  • Respiratory system
  • Excretory system
  • Nervous system
  • Skeleton system

The teacher should here use the Wall Charts to show the various systems.

7. Tying it all together The teacher can here make an analogy to people in the community who do different specialised jobs-policemen, farmers, doctors, pilots, teachers, etc. Similarly, the body needs specialised cells and tissues to work efficiently. For the body to work efficiently, all the systems must perform their duties well, they must work in unison.

8. Assessment The students should be made to draw the various systems and if possible label each one appropriately.

9. Author(s) S. T. Bajah stan@alpha.linkserve.com N.E.U.Inyang University of Cross River, Uyo.

10. References Ministry of Education and Culture (2000). Step Ahead New Secondary Science Student's Book 1 Zimsci Harare: Longman Zimbabwe (Pvt) Ltd.

STAN (1998) Nigerian Integrated Science Project. Book Two. Ibadan: Heinemann Educational Books (Nigeria) Limited.