Basic Science and Technology
Primary 6/ Basic 6
Previous lesson :
The pupils have previous knowledge of Improving Crops Yield
The Human Circulatory System
Specific Behavioural objectives :
At the end of the lesson, the pupils should be able to
- define the circulatory system
- recognize the human heart and the vessels
- write out the function of the heart and the blood vessels
- explain the process of the circulation of blood vessels
- draw and label the chambers of the heart
Instructional Materials :
- Wall charts
- Related Online Video
- Flash Cards
Methods of Teaching :
- Class Discussion
- Group Discussion
- Asking Questions
- Role Modelling
- Role Delegation
Reference Materials :
- Scheme of Work
- Online Information
- 9 Year Basic Education Curriculum
Content Development :
The heart is the pumping station of the body .
The heart starts function right from birth and does not go on vacation or stops until death .
The heart is made up of special muscles that pump blood round the body.
The blood is the transportation system of the body.
The blood transports nutrients and oxygen through out the whole body.
The Heart are specially created that they contain four parts or chambers .
These four chambers of the heart are namely :
(i) Right auricle
(ii) Left auricle
(iii) Right ventricle
(iv) Left ventricle
The muscular walls of the ventricles are thicker and more muscular than that of the auricles.
Functions of the Heart
The functions of the heart include the following:
(j) The major function of the heart is to pump blood to all parts of the body.
(ii) It also keeps blood in continuous flow round the body.
Blood vessels are tubes through which blood moves round the body. These
vessels are; arteries, veins, and capillaries and they have various functions in
the body. Arteries carry blood away from the heart, while veins carry blood
towards the heart.
Capillaries join arteries to the veins.
i) Arteries: These are blood vessels that carry blood away from the heart.
That is, blood flows from the heart to all parts of the body through arteries.
ii) Veins: These are blood vessels that carry blood from other parts of the
body to the heart.
iii) Capillaries: They are the tiny network of blood vessels that connect the
veins to the arteries. They carry blood between arteries and veins.
The circulatory system is the route by which blood moves round the body. It is
made up of the heart blood, and blood Vessels.
Functions of the blood circulatory system
The blood circulatory system in the human body has several functions. They
are as follows:
1. The blood system carries oxygen, absorbed into the blood in the lungs, to all
the living cells in all parts of the body.
2. The blood system carries food substances, after digestion, from the
alimentary canal to all the living cells in the body.
3. The blood system carries the white blood corpuscles to all parts of the body
where they defend the body against infection.
4. The blood system carries antibodies all round the body. The antibodies
defend the body against infection.
5. The blood system carries waste products, such as carbon dioxide, urea,
water and excess salts from living cells where they are produced to the parts
of the body, such as the lungs and kidneys where they are removed.
Defense of the body against infection
When disease-causing organisms enter the human body, the white blood cells
attack and swallow them, or produce chemicals called antibodies that kill the
By clotting at the point of an injury, the blood protects the body against
further loss of blood.
Distribution of heat
Some parts of the body, e.g. the muscles produce more heat than others. The
blood circulatory system distributes heat evenly throughout the body.
There are two types of blood circulation in the body. These are: Pulmonary
circulation and Systemic circulation.
(i) Pulmonary Circulation· This is one in which blood flows from the heart to
the lungs and back to the heart.
(ii) Systemic Circulation: This is one in which blood is pumped from the heart
to the other parts of the body and back to the heart.
The right auricle and ventricle contains blood with less oxygen and more
carbon dioxide. The left auricle and ventricle contains blood with more
oxygen that comes from the lungs.
The heart is filled with blood, as a result of the relaxation of the involuntary
muscles of the heart called cardiac muscle. When the muscles of the heart
contract, it (the heart) pumps blood out through the right and left ventricles
into the pulmonary arteries and aorta respectively.
The blood in the pulmonary arteries goes to the lungs and the blood in the
aorta goes to other parts of the body.
The presence of valves prevent the blood from flowing back to the heart.:
When the heart is relaxed, blood returns to the heart from the veins through
vena-cava to the right auricles and through the pulmonary veins to the left
The blood that moves into the body cells is more oxygenated because
the blood flows by the indication of the arrows.
Functions of the arteries and veins
The arteries carry blood away from the heart and the veins carry blood
towards the heart.
Functions of the capillary blood vessels
If blood were to flow all the time within the blood vessels, it would not be of
much use to the body. The capillaries have thin walls through which the liquid
part of the blood can diffuse out of the blood vessels to reach the living cells in
the various organs. In this way, the capillaries make it possible for the cells of
the body to be supplied with food, water, oxygen and all other essentials. They
are also useful in the removal of waste products from the cells
Differences between arteries and veins
1. They carry blood away from the heart. They carry blood towards the heart .
2. They have thick elastic walls. They have thin, not very elastic
3. They carry blood that contain they carry blood in which
(except the pulmonary vein)
oxygen (except the pulmonary oxygen has been used up artery
4. Pressure of blood in the vessels is high Pressure of blood in the vessels is
5. They do not have valves. They have valves to prevent the back-flow
6. Arteries are located deeper in the Veins are located nearer the flesh
surface of the body than arteries. than veins.
7 Pulse is detectable. Pulse is usually not detectable
The topic is presented step by step
The class teacher revises the previous topics
He introduces the new topic
The class teacher allows the pupils to give their own examples and he corrects them when the needs arise
The class teacher wraps up or conclude the lesson by giving out short note to summarize the topic that he or she has just taught.
The class teacher also goes round to make sure that the notes are well copied or well written by the pupils.
He or she does the necessary corrections when and where the needs arise.
1. Draw and label the human heart ?
2. State four functions of the heart ?
3. Which blood vessels return blood to the heart ?
4. Mention two types of circulation ?
5. List the things that make up the human blood.
6. Name the four chambers that make up the human heart.
7. Describe the paths along which blood circulates round the human body.
8. Describe the functions of the human heart.
9 State four differences between arteries and veins.
10. Explain the importance of blood capillaries.
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