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Circulatory System



STARTING POINTS In this chapter, you are going to explore the components of blood and the important role it has in the transportation around the different parts of the circulatory system. You will learn how to: • identify the functions of each component of the blood • explore the important role haemoglobin has in the circulatory system • describe the structure and function of the heart and blood vessels • explain the terms cardiac output, heart rate and stroke volume.

CHAPTER CONTENTS The activities you complete will primarily relate to the circulatory system, but you will also be able to identify links to other units to help reinforce your learning as a whole. In this chapter, you will: • create a mind map for the components of blood and their link to the circulatory system • create a flow diagram that shows the pathway from the lungs around the circulatory system • use a drawing style activity to reinforce your understanding and your ability to explain the circuits/sides/blood type • complete a heart template that identifies specific locations and their function • use an acronym to remember the sides of the heart: LORD • design a circuit training session using the structure of the heart with eight stations • identify six different sports that require cardiovascular fitness to perform at a high level • investigate the effects of exercise on the heart rate and cardiac output • create an information map to collate the information from this section.

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1.3.1  Components of blood LEARNING OBJECTIVES By the end of this section you will be able to: • identify the different components of blood • understand the role of haemoglobin • describe the structure of the blood vessels and their functions.  Spotlight The components of blood and the important role it provides on within the circulatory system.

Starting point The body relies upon food and oxygen (oxygenated blood) to be transported via the circulatory system to the cells in the body whilst extracting waste and carbon dioxide (deoxygenated blood) away from the cells.

Key Term

circulatory system: the body’s transport system that consists of the heart, blood vessels and blood

1. Copy the diagram of the

Exploring the skills Blood has two main roles in transportation and protection. The image of blood in the test tube identifies the components that form the structure of our blood. Each of these has an important function: • Plasma consists mainly of water to allow substances to dissolve and be transported easily. • Red blood cells contain haemoglobin which reacts with oxygen from the lungs to form oxyhaemoglobin.

Blood low in oxygen (deoxygenated)

Blood rich in oxygen (oxygenated) Lungs


L Heart


L Body


Circulatory System

circulatory system with labels, and using specific colours to show the transportation of blood.

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• White blood cells (part of the immune system) defend the body against pathogens (diseases) by engulfing them or creating antibodies to attack them. • Platelets contain an enzyme that causes blood to clot when there is damage to blood vessels or they are exposed to air.

Key Term

blood: a liquid that contains four components: plasma, red blood cells, white blood cells and platelets. Each have a specific function



White blood cells

Red blood cells

Create a mind map that includes all the components of blood, Reflective Log their functions and how they link to the circulatory system and

Developing the skills The transportation of oxygenated blood (oxyhaemoglobin) to the cells and the removal of carbon dioxide (waste product) using the same process of attachment, is made possible through a series of blood vessels. They are divided into three groups (identified in the following images), each with a distinct function. Key Term

blood vessels: three different types of vessels which carry blood - arteries, veins and capillaries


1.3.1  Components of blood

the body as a whole.

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To help remember these, note the following: a is for artery that travels away from the heart. Veins carry blood into the heart, and contain valves (to stop blood flowing backwards). Artery

Thick muscular wall


Thin wall

Capillary Walls − a single cell in thickness


Circulatory System

Applying the skills 2. To reflect upon this learning, create a flow diagram with illustrations, that starts at the lungs and travels around the circulatory system. Include the following key terms and think about how you can explain your choices to others: 1) lungs 2) oxyhaemoglobin 3) veins 4) heart 5) capillaries 6) CO2 7) arteries. Checklist for success ✓✓Be aware of the function of blood and how it helps the body in many different ways. ✓✓Consolidate the structures of each of the blood vessels and the importance of their role. Sound progress • I can identify the components of blood and their roles to support the body. Excellent progress • I know the importance of haemoglobin and can describe how it transports both oxygen and waste products around the circulatory system.

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1.3.2 The heart structure LEARNING OBJECTIVES By the end of this section you will be able to: • identify the location of each section of the heart • understand the functions of atria, ventricles and valves • describe the pathway of blood through the heart.  Spotlight The journey of blood through the heart consolidating on understanding of the different locations and functions it encounters before entering the body.

Starting point The circulatory system introduced the transport system of the body. This becomes more specific as we examine how oxygenated blood and deoxygenated blood is pumped around the body by the heart through the arteries, veins and capillaries, to their destinations. double circulation: the heart has a double pump and

circulation: Pulmonary circuit (right side) pumps blood to the lungs and back to the heart. Systemic circuit (left side) pumps blood to the body and back to the heart Delivers carbon dioxide Capillaries in the lungs



Ar ry



Capillaries in the body




Exploring the skills The heart consists of four chambers. The two at the top are atria (singlular form is atrium) and the two at the bottom are ventricles. They are separated by a thick cardiac muscle (the septum) which contains the blood and allows it to flow in one direction. The valves prevent the blood flowing backwards and are positioned where the blood enters and leaves the heart.

Collects oxygen


By looking at the diagram below draw your own version that you can use to explain the circuits/ sides/blood type in the style of a drawing game, like the game Pictionary™, for your partner to guess the answer.

Collects carbon dioxide and waste Blood low in oxygen (deoxygenated)

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Delivers oxygen and food Blood rich in oxygen (oxygenated)

1.3.2 The heart structure

Key Term


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Key Term

heart: a muscular organ that expands as it fills with blood and contracts to force blood away through the arteries, it returns through the veins to the heart

vena cava – from upper body

aorta – to all of body pulmonary artery – to lungs pulmonary veins – from lungs left atrium

semilunar valve right atrium atrioventricular valve

semilunar valve atrioventricular valve

right ventricle

left ventricle

vena cava – from lower body

3. Using the heart template, label the specific locations and provide

their function: atria/ventricles/valves/pulmonary artery/aorta/ pulmonary vein/vena cava. Colour the sections to identify oxygenated (red) and deoxygenated (blue) blood. Include arrows to indicate the direction the blood will flow.

Here is an acronym to remember the sides of the heart: LORD Reflective Log Left Oxygenated, Right Deoxygenated. Can you devise other

Developing the skills The heart has a particular sequence that allows the blood to follow its pathway around the body. First the atria both contract at the same time then the ventricles both contract at the same time to move the blood through the heart. This double circulation sees blood passing through the heart twice in each circuit at a high pressure to flow faster to the body. The heart pumps blood in two stages: Stage1: deoxygenated blood from the body via the vena cava into the right atrium which contracts forcing the blood past the valve into the right ventricle. The right ventricle contracts forcing the blood through the pulmonary artery to the lungs. Stage 2: oxygenated blood from the lungs via the pulmonary vein into the left atrium which contracts forcing the blood past the valve into the left ventricle. The left ventricle contracts forcing the blood through the aorta to the body.


Circulatory System

helpful acronyms for the sections of the heart: atria/ventricles/ valves/pulmonary artery/aorta/pulmonary vein/vena cava.

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The Heart Superior vena cava

Aortic valve Aorta

Pulmonary vave

Pulmonary artery

Left atrium Right atrium

Pulmonary vein

Right ventricle

Left ventricle Interior vena cava

Aorta Thick muscular wall of ventricle

Checklist for success ✓✓Understand the stages connected to the double circulation of oxygenated and deoxygenated blood around the body. ✓✓Identify the structure of the heart and the flow of blood around the body. Sound progress • I can describe the sections of the heart and the importance of their functions.


Excellent progress • I can demonstrate my understanding of the pathway that blood follows through a verbal or diagrammatic explanation.

1.3.2 The heart structure

Applying the skills 4. Design a circuit training session with eight stations. 5. Divide the class into two groups with half wearing blue bibs, to represent deoxygenated blood (which allows the blue-bib-people to enter the heart via the vena cava into the first atria) and the other half wearing red bibs, to represent oxygenated blood (which allows the red-bib-people to enter the heart through the pulmonary vein into the first atria).

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1.3.3  Cardiac Output LEARNING OBJECTIVES By the end of this section you will be able to: • explain the terms heart rate, stroke volume and cardiac output • identify how cardiac output can be calculated.  Spotlight What happens to the heart during exercise and how it effects our on cardiovascular fitness

Starting point Participating in exercise or physical activity will benefit you to understand this. There are three definitions to explore: heart rate, stroke volume and cardiac output.

Key Term

heart rate: measures the heart beats per minute (bpm) when the ventricles are contracting. Resting heart rate is generally 50 – 90 bpm (teenager) and 60 – 80 bpm (adult)

We can take measurements of our heart rate by feeling for the pulse point which is where the blood flows through an artery near to the skin: carotid (neck) or radial (wrist). An elite athlete may have a resting heart rate as low as 40 bpm (beats per minute), whereas a person of the same age with an average level of fitness might be 70 bpm. This can be affected by their age, gender, size.

Temporal Carotid Apical Brachial Radial

Key Term


Dorsal pedal

Posterior tibial

stroke volume: the volume of blood on average 70 ml) pumped out of the heart by each ventricle in one beat. For an athlete this will be 90ml, on average.


Circulatory System

Exploring the skills Cardiovascular fitness benefits the entire body over a period of time that requires increased oxygen to be supplied to the muscles. During this process the heart rate can be at a maximum of: 205 - your age (15 years = 190 bpm). The long term effect of this is that your heart will increase in size and strength, improving its stroke volume.)


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Regular exercise will increase the stroke volume due to the heart growing in size through hypertrophy (increase in muscle size) and retaining blood in the chambers so they fill more and empty more. The heart is more efficient and stronger with each contraction forcing more blood out into the body. Identify six different sports that require cardiovascular fitness to Reflective Log perform at a high level.

Developing the skills The fitness of a person is determined by how fast their heart rate can recover to normal (resting) after exercise. This is a long term benefit of exercising. Athletes monitor their heart rates as exercise increases to establish different levels of training intensity. This provides additional information such as more blood will result in increased oxygen supply. Having a clear understanding of their cardiac output will benefit their training.

Key Term

cardiac output: is the amount of blood ejected from the heart each minute

The cardiac output is controlled by the stroke volume and the heart rate of an individual and will change over a long period of exercise. This is shown in the following equation:

Heart rate (HR) × Stroke volume (SV) = Cardiac Output (CO) (HR) 50 (bmp) × (SV) 90 (ml) = (CO) 4.9 litres

Therefore this shows that the fitter a person is the stronger their stroke volume will be, allowing more blood to be pumped and oxygen delivered.

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1.3.3  Cardiac Output

When resting, your body has nearly 5 litres of blood travelling around it. If this were an athlete:


Heart rate (HR) × Stroke volume (SV) = Cardiac Output (CO) (HR) 70 (bmp) × (SV) 70 (ml) = (CO) 4.9 litres

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Applying the skills 1. Investigate the following effects of exercise on the heart rate and explore the cardiac output. As a class divide into three groups to complete a 400m race whilst wearing heart rate monitors (if possible) or otherwise taking your pulse rate before and after. Select four people from each of the groups to record their resting heart rate and their final heart rate after the following sequence: • Group 1 will run as fast as possible • Group 2 will jog at a rate at which they can still talk to each other • Group 3 will jog for 50m then sprint for 50m until they complete 400m. Present your findings as a graph and discuss the difference in the heart rate and why this was. What would be the cardiac output? Which group returned to resting heart rate the quickest? Create an information map to collate all of the information Reflective Log from this section and consolidate how this can contribute to the circulatory chapter as whole. Include the following sections: key words/useful definitions/diagrams/examples of exercise/sport.

Checklist for success ✓✓Explain the following terms heart rate/stroke volume/cardiac output. ✓✓Know the calculations when working out cardiac output and maximum heart rate. Sound progress • I can locate where a pulse is and identify my resting and active heart rates.


Circulatory System

Excellent progress • I can use data about my heart rate and stroke volume to calculate my cardiac output.

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Collins Cambridge IGCSE Physical Education Sample  
Collins Cambridge IGCSE Physical Education Sample