© ORCA Education Limited 2004 The Cardiovascular System © ORCA Education Limited 2004 New Words

© ORCA Education Limited 2004

The Cardiovascular System

© ORCA Education Limited 2004

NewWords

© ORCA Education Limited 2004and suppliers all rights reserved

The Cardiovascular System?There are two parts to the cardiovascular system:

the heart which pumps the blood around the body (cardio)

the blood vessels divided into veins, arteries and capillaries (vascular).*


The Functions of the SystemThe cardiovascular system has 3 functions

1. Temperature Control The blood transfers

heat around the body.

2. Transportation The blood carries essentials like

oxygen and nutrients to the muscles.

The blood carries away carbon dioxide and other waste.

3. Protection The blood carries

antibodies which the body needs to fight an infection.*


The Heart

The body has 4.5 litres of blood (just over 2 large lemonade bottles full).

The heart pumps blood around the body. Each section of the heart contracts in sequence and

each cycle is a heartbeat.

It takes 1 minute for this to be pumped around the body.

Valves stop the blood from flowing backwards.*


The Parts of the HeartBlue areas take deoxygenated blood back to the heart.

Red areas carry oxygenated blood from the lungs to the heart and then to the body.

Right Atrium

Left Ventricle

Right Ventricle

Aorta (O2 to the body)

Pulmonary Vein (from the lungs)

Pulmonary Artery (CO2 to the lungs)

Left Atrium

Aorta (O2 to the body)

Superior Vena Cava (from the body)

Inferior Vena Cava (from the body).


Blood flow through the heart Oxygen rich blood is pumped into the

left atrium from the lungs via the pulmonary vein.

It is then pumped into the left ventricle.

The blood is pumped from here to the aorta and to the body and muscles.

The deoxygenated blood passes from the body into the vena cava and back into the right atrium of the heart.

It is then passed into the right ventricle.

Passing through the pulmonary artery the blood is returned to the lungs for oxygen.*


Circulation

From the capillaries blood passes back into larger venules.

From the heart the blood circulates to all our organs and our muscles. Large arteries take the blood with oxygen from the heart.

The arteries split into arterioles.

The arterioles carry blood and oxygen into the tiny capillaries.

The deoxygenated blood begins its return to the heart.

The venules join to form veins that return blood to the heart and lungs for more oxygen.*


The 4 Components of Blood

Red cells carry oxygen from the lungs to the muscles.

White cells defend against disease.

Platelets clot the blood to stop bleeding.

Plasma which is 92% water but contains glucose and CO2.*


Why is Blood Pressure Important?

The blood is put under pressure by the beating action of the heart.

When the heart contracts it is known as systolic pressure.

When it relaxes this is diastolic pressure.

This can be measured the average blood pressure is 120/80.*


Heart Disease An important role for sport is

encouraging good health. Poor diet and lack of exercise

can increase blood pressure. Fats can collect in the arteries

making them narrower. The heart works harder to pump

the blood around. This can lead to a heart attack.*


Four healthy thirty something business people.

Fitness and Cardiac Output

The heart of one of these is different to the others.

Lucy RachelJulie Peter

One has a lower base rate. Their heart beats more slowly.

The volume of blood pumped on each stroke is higher (Stroke volume).

They pump more blood every minute.

This person can sustain a higher pulse rate during exercise.*


With fitness through training the heart becomes stronger and slightly larger.

The pulse rate at rest gets lower from an average of 70 to the mid 40’s.

Fitness and Cardiac Output

Julie

73Rachel

68Lucy

49

Peter

71

Lucy has been an athlete since she was 14. She is an international standard race walker who can walk 20 km in 95 minutes.

This is faster than her colleagues can run.*

What is their resting pulse rates?


A common track training session for Lucy is 10 X 800m interval training.

During this session her heart rate will reach 200 bpm.

She will only allow her heart to recover to 140 bpm before starting the next 800metres.

Stroke Volume

At rest her work friends’ hearts will pump an average of 70ml of blood on each beat. This is the stroke volume.

70ml x 70 bpm = 4900ml or 4.9 litres of blood per minute.

Lucy’s powerful heart has a stroke volume that is nearly 100. Her heart at rest works far less than her friends to do the same job.*


Lucy’s Cardiovascular fitness means that she has reduced her risk of heart disease and everyday life will be easier.

What advice should she give her boss Joe?

One thing he must do is take exercise 3 times a week for 30 minutes that will push his heart rate up to his target heart rate THR. How does he calculate this?

Joe is 51. His Maximum Heart Rate (MHR) is 220-51=169.

Exercise at this rate would be too much for Joe. His THR is 75% of his MHR = 126.*

Time to get fit?


Vocabulary

Blood Vessels Aorta Atria Ventricles Pulmonary Artery Capillaries Veins Venules

Do you know what these terms mean?

Red blood cells White blood cells Platelets Systolic pressure Diastolic pressure Stroke volume THR MHR*


Task

Write a letter to Lucy’s boss Joe explaining what he must do to help prevent heart disease.

Draw a flow diagram that shows the circulation of blood through the heart.*

A task for you to do


End

Acknowledgements

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© ORCA Education Limited 2004 The Cardiovascular System © ORCA Education Limited 2004 New Words