1. Circulatory System

2. Learning Outcomes
On completion of this chapter students should be able to:
OB13 describe the function and composition of blood, and know that blood contains white blood cells, red blood cells and platelets in a liquid called plasma
OB14 understand the structure and function of the heart, identify the four chambers of the heart, and explain the difference between the left and right ventricles
OB15 describe the passage of blood through the heart and lungs via arteries and veins, identify the pulmonary artery and vein, aorta and vena cava, and distinguish between arteries, veins and capillaries

3. Learning Outcomes contd..
OB16 demonstrate the effect of exercise and rest on pulse rate and understand that a balance of each promotes good health
OB17 recall that the average pulse rate for an adult at rest is 70 beats per minute, and explain why exercise results in increased pulse and breathing rates

4. Lesson 1
Composition of Blood

5. What is the circulatory system?
The Circulatory System is responsible for transporting materials to and from different places in the body.
It is made up of:
Blood
Blood vessels
The heart
Students are asked for their own definition of the circulatory system and what it is responsible for.
They are then asked what the circulatory system is made up of (hands up basis).
It is then revealed and each of the three components are explained.

6. Blood consists of: Red Blood Cells White Blood Cells Platlets Plasma
Students are asked if they know what makes up blood.
Each component is revealed slowly and students are asked what they know (if anything) about each.
Plasma

7. Red Blood Cells Most numerous cell in the body Small doughnut shape
Contain haemoglobin which transports oxygen around the body
Red blood cells are studied more thoroughly- this includes a physical description and an explaination of their function.
Students are asked to identify the colour of blood. It is explained that red blood cells give blood its colour.
The shape of red blood cells is identified and a simple diagram is drawn on the blackdoard for clarity.
Students are asked if they are familiar with the term microscopic. If not it is explained and indicated that red blood cells are microscopic.
The term haemoglobin is explained briefly and students are told that it is responsible for carrying oxygen around the body.

8. White Blood Cells
Larger than red blood cells but also much fewer in number
Fights infection by destroying bacteria and viruses that have invaded the body
White blood cells are described in more detail.
It is indicated that they are much bigger than red blood cells but there are less numerous (reference is made to the diagram for this)
Their shape is explained, diagram drawn on the board for clarity.
Their function is described. (it is explained to students how they work, ie produce antibodies and engulf bacteria.
Reference is made to an infected wound-white cells often gather and produce puss.
White Blood Cell

9. Platelets Tiny fragments of cells
Cause blood to clot by producing tiny fibrinogen fibres
These stretch across a cut to stop bleeding
Students are instructed to look at the diagrams above for clarity.
The term fibrinogen is explained. Comparisons are made to netting or spider webs.
Students are asked if platelets didn’t exist what would happen if we got a nose bleed or cut our fingers?

10. Plasma It also contains useful things like: glucose
carbon dioxide
glucose
amino acids
proteins
minerals
vitamins
hormones
waste materials
A straw-coloured liquid that carries the cells and the platelets which help blood clot.
Reference is made to water to describe plasma-it is the reason blood is a liquid and not a solid. if it wasn’t liquid what would happen? It wouldn’t be able to flow around the body.
The contents of plasma are explained- students are asked to come up with answers. They are prompted where necessary-i.e what are the nutrients that may be found in the plasma? Does it carry anything that we don’t need?
Where does it pick up carbon dioxide?

11. Functions of Blood To transport food, oxygen and wastes
To transport heat to the skin to keep the body temperature at 37°C.
To fight infection
The functions of blood are outlined.
Based on the material covered during this class, students are asked to outline answers.
Prompting takes place if necessary.
e.g. whats the function of red blood cells, white blood cells, platelets?
What is body temperature? Is the blood involved in keeping body temperature constant?

12. Lesson 2
Blood Vessels

13. There are 3 types of blood vessels found in our body:
Veins
Arteries
Capillaries
Students are asked if they know what a blood vessel is…if not it is explained.
Students are asked to give an example of a blood vessel in the human body. If they fail to respond, prompts are given e.g. what can we see through the skin on our hands and our wrists?

14. Veins Veins carry blood towards the heart
They have thin walls and a wide inner cavity which allows blood flow to the heart easily
They also contain valves which stops the blood flowing backwards
Veins are described thoroughly using the above diagram.
The terms valves and lumen are explained.
Students are asked if the veins carry blood from the toes to the heart what will stop the blood from flowing backwards?
Students are asked if they have ever heard of varicose veins? They form when the valves fail to work effectively.
Wide inner cavity (lumen)
veins with valves

15. Arteries Arteries carry blood away from the heart
They have thick elastic walls which allows them to stretch and recoil at each heartbeat
These muscles contract to push the blood along
If veins carry blood towards the heart then what direction do you think arteries carry blood?
It is explained why the walls of the arteries need to be thicker and stronger than veins-i.e.the pressure from the heart.
Students are asked if they are familiar with the term contract, if not it is explained.
Why do you think arteries don’t need valves?
It is explained that the force of the heartbeat and the contractions of the muscles will prevent the blood flowing backwards.
Narrow inner cavity (lumen)
Thick muscular walls
No valves present

16. Capillaries Capillaries link arteries and veins
Have very thin walls-just one cell thick
Materials can be exchanged from the blood to other body cells and vice versa via capillaries
Capillaries are responsible for connecting arteries and veins.
If their walls are so thin, do you think they will be able to contract and push blood along like arteries? No.
It is explained that capillaries have thin walls to allow materials to be exchanged .e.g. oxygen and carbon dioxide.
Where in the body is oxygen and carbon dioxide exchanged.
Wall just one cell thick

17. The Structure of the Heart
Lesson 3
The Structure of the Heart

18. The Heart
The heart is a muscular pump that transports blood around the body
It consists of 4 chambers:
Right atrium Left atrium
Right ventricle Left ventricle
The heart is introduced.
Each student is asked to clench their fist, the size of their fist is roughly the size of their heart.
It is explained that the heart is a pump that pumps blood all around the body.
It is divided into 4 compartments- 2 at the top called atria and 2 at the bottom called ventricles.
Blood vessels enter through the atria and leave through the ventricles.
YouTube video

19. The Heart Atria Ventricles The lower chambers The upper chambers
Receives blood from the atria
Pumps blood out through arteries
Left ventricle has thick walls (more strength required to pump blood around the body)
Atria
The upper chambers
Receives blood from veins
Pumps blood into ventricles
Have thin walls
The above points are outlined.
It is explained why the wall around the left ventricles is thicker-more power is required to transport blood to every corner of the body, unlike the right ventricle which just needs to sent blood to the lungs (which is a relatively short distance)

20. Structure of the Heart Aorta Pulmonary artery Pulmonary vein Vena Cava
Right Atrium
Left Atrium
Each chamber of the heart is pointed out using the above diagram.
It is then pointed out what blood vessels are associated with each chamber.
From what I have told them previously during the class, students are asked to identify what blood vessels are leaving the heart and what blood vessels are entering.
Right Ventricle
Left Ventricle

21. How does the heart work?
Deoxygenated blood enters right atrium via vena cava
Blood is pumped to right ventricle and then to the lungs via the pulmonary artery
3. Oxygenated blood enters left atrium via pulmonary vein
4. Blood is pumped to left ventricle where it leaves via the aorta
The terms oxygenated and deoxygenated are explained.
Students are asked which blood vessels carry oxygenated blood and which carry deoxygenated?
The pathway of blood through the heart is explained thoroughly and slowly.
Students are asked random questions throughout this process to test their understanding.

22. Pulmonary artery Aorta Vena cava Pulmonary Vein
On a broader scale this diagram shows where the blood flows throughout the body.
Students are asked to identify the relevant veins and arteries on the diagram. Prompting is given where necessary e.g. into what chamber is it flowing….so does that mean it is an artery or vein? What is the name of that particular artery/vein? etc.

23. Tips for remembering VEAL Veins Enter, Arteries Leave LORD
Left=Oxygenated, Right=Deoxygenated
Pulmonary = related to lungs
e.g. Pulmonary vein enters from lungs
These terms are explained i.e. the first letter of the above words represents a useful sequence relating to the circulatory system.

24. The Pulse & How to demonstrate the effect of exercise on the pulse
Lesson 4
The Pulse
&
How to demonstrate the effect of exercise on the pulse

25. The Pulse
Every time the heart contracts, the blood surges forward in the arteries. By placing your fingers over an artery, you can feel this pulse
The term pulse is explained ie. What it is and where it can be found.
Each student is given time to find their own pulse. Directions are given as to where to find it.

26. The Pulse Lets find out…...
For an adult the average pulse rate is 70 beats per minute (b.p.m.).
Children have faster heartbeats than adults.
What happens to our pulse rate when we exercise?
What do we mean by the term pulse rate?
Students are asked to come up with explainations.
It is explained why the pulse rate is greater in children and why fitness level effects the pulse (heartbeat)
Students are asked to suggest what might happen to it when we exercise, but an answer is not revealed.
Lets find out…...

27. Mandatory Practical
Title: to demonstrate the effect of exercise on the pulse rate
Beats per minute at rest
vs.
Beats per minute after exercise
Students are asked to carry out this experiment, they are divided into pairs and each one is instructed to take each others pulse for one minute. (one students takes pulse, the other takes time).
Repeat this procedure 2 times (after 3 minutes and again after 6 minutes)
Title and method is written into experiment copies.

28. Results Beats per minute Person 1 Person 2 At rest
Immediately after exercise
3 minutes after exercise
6 minutes after exercise
Students copy down the above table into their experiment copies and fill in the blanks accordingly.
Pulse rates are recorded immediately after the exercise, again after 3 minutes and again after 6 minutes. These results are inserted into the table above.
Results are discussed.
What do you notice about the pulse rate after 6 minutes? Can you suggest a reason for this?

29. Exercise increases the pulse rate.
Conclusions
When a person exercises, the muscles need more oxygen to get more energy from food. A faster heartbeat delivers oxygen to the muscles quicker.
Exercise increases the pulse rate.
Students are asked for conclusions to their experiment. (each pair are asked for their personal conclusion before the text is revealed on the above slide).
It is also explained to students that too much exercise is not healthy. The body also needs rest.
Students write conclusions into their experiment copies.

30. Why we need exercise To prevent heart disease we should:
Exercising the heart makes it stronger and reduces the likelihood of heart disease.
To prevent heart disease we should:
Take regular exercise
Never smoke
Eat only small amounts
of saturated (animal) fats
Why do we need to exercise?
If we don’t exercise what effect could this have on our heart?
The benefits of exercise are discussed in a class discussion.
The damaging effects of smoking and eating fatty foods are also discussed.

31. Assessment
The circulatory system is made up of blood, blood vessels and the _____.
Arteries _____ the heart and ______ enter the heart.
The capillaries ______ arteries and veins.
Blood is made up of red blood cells which carry _____, white blood cells which fight _______, platelets which causes blood to _____ and ______ which is the liquid part of blood.
The heart is made up of _____ chambers, 2 atria and 2 ventricles.
Students are given 10 minutes to copy down the above passage into their copies and fill in the blanks.

32. Solutions
The circulatory system is made up of blood, blood vessels and the heart.
Veins enter the heart; arteries leave the heart and
The capillaries link arteries and veins.
Blood is made up of red blood cells which carry oxygen, white blood cells which fight infection, platelets which causes blood to clot and plasma which is the liquid part of blood.
The heart is made up of four chambers, 2 atria and 2 ventricles.
Students are asked individually for the answers before being revealed and they are asked to correct any mistakes.

33. Bibliography http://library.thinkquest.org/5777/images/circulatory.gif l