activity 3

SULTANS OF SCIENCEISLAMIC SCIENCE REDISCOVERED

ActivityHeart-LungBlood Circulation System 3

© 2011 MTE Studios

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The way in which the blood circulates through the human body is basic to any understanding of how we function.

The ancient Greeks thought that the liver produces blood and that the blood was filled with ‘natural spirit’ when it came into contact with food in the liver. They did recognize, however, that the heart played an important role in pumping the blood around the body.

HEART

LUNGS

RESPIRATORY SYSTEM

BLOOD CIRCULATION

The great Greek physician, Galen, who worked in the second century CE, tried to explain how the blood is pumped around the body by suggesting that the venous and arterial systems are separate but that blood seeps through invisible pores from the right to the left side of the heart, where it comes in contact with air.

We now know that Galen was wrong and that there is not a single blood circulation system:

but a double circulation system:

The heart is the main blood pump, but it first pumps the blood to the lungs, where it is aerated, then back to the heart, and, after that, to the rest of the body. The blood returns to the heart via the venous system.

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‘Discovery’ by Dr William Harvey The famous English surgeon, Dr William Harvey (1578-1657), is widely recognized in the West as the discov-erer of the double circulation system of the blood. Harvey studied medicine under Fabricius and Galileo in Italy and at Cambridge in England. He was a famous medical doctor who was the private physician to the King of Eng-land, James I. He published his theory on the circulation of the blood in an essay entitled ‘The Motion of the Heart and the Blood’ in 1628.

Discovery by Ibn an-Nafis Ibn an-Nafis was a Muslim medical scholar who was born in Damascus, Syria, in 1210 and died in Cairo in 1288. He was trained in the Nuri Hospital in Damascus but spent most of his working life in the famous Nasiri Hospital in Cairo, Egypt. He was a very busy and influential medical doctor who wrote several authoritative books on healthy eating and medical procedures.

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BODY

PULMONARY CIRCUIT

SYSTEMIC CIRCUIT

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IBN AN-NAFIS

Blood from the right cham-ber must flow to the lungs, be mingled there with air, pass through the pulmo-nary vein to reach the left

chamber of the heart.



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Discovery of a book by Ibn an-Nafis In 1924 a very important book was discovered in the Prussian State Library in Berlin, Germany. The book was called ‘Commentary on the Anatomy of the Canon of Avicenna’ and was written by Ibn an-Nafis. The book discussed the work of the famous Muslim scientist, Ibn Sina (known in the West as ‘Avicenna’).

In this book, Ibn an-Nafis clearly describes the double circulation of the blood as we know it today, and states that there are no perforations between the left and right ventricles of the heart: “ … the blood from the right chamber of the heart must arrive at the left cham-ber, but there is no direct pathway between them. The thick septum of the heart is not perforated and does not have visible pores as some people thought or invisible pores as Galen thought. The blood from the right cham-ber must flow through the pulmonary artery to the lungs, spread through its substance, be mingled with air, pass through the pulmonary vein to reach the left chamber of the heart …”.

It is clear that Ibn an-Nafis thoroughly understood the double circulation of the blood over 730 years ago!

In one section of the book Ibn an-Nafis disagrees with Ibn Sina, who stated that the heart has three ventricles and that blood seeps from one part of the heart to the other (as proposed by Galen).

A medieval view of human anatomy showing the blood circulation, from a manuscript by the 14th century Persian physician, Mansur ibn Ilyas.

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‘Human Health Touch Wall’ display Study the ‘Human Health Touch Wall’ interactive display in the exhibition. Touch the heart and read more about the discoveries of Ibn an-Nafis and the double blood circulation system.



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Understanding the pulmonary-heart blood circulation systemIn the attached diagram a simplified scheme of the double blood circula-tion system is shown. Label the following components of this diagram:

Check your labels against the diagram in the ‘Human Health Touch Wall’ display.

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The pulmonary-heart blood circulation system

ABLETO

LABEL



© 2011 MTE Studios

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Listen to your heart beat Use the stethoscope attached to the ‘Human Health Touch Wall’ display to listen to your heart beat. A stetho-scope is a medical instrument that is comprised of two ear plugs (to put in your ears) and a tube connected to a flat, sensor device (the chest piece) that has a sensitive membrane that vibrates in response to your heart beat.

Place the sensor against the skin on the left side of your chest under your clothes – you should be able to hear your heart beating!

Listen to the pattern of your heart beat – you should hear a double beat, which is the sound of the two sets of valves in your heart opening and closing as they pump blood to your lungs and body.



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The average resting heart rate of a newborn baby is 140 beats per minute. As you grow older your heart rate slows down to about 100 at age 4 and between 70 and 110 in older children, whereas the average for an adult is 60-80 beats per minute.

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BLOOD PRESSURE MONITOR

Maximum (systolic) Blood Pressure

Minimum (diastolic) Blood Pressure

Pulse Display(Heart Rate)

140bpm

100bpm

70-110bpm

60-80 bpm

Now set a stop watch and count how many times your heart beats every 60 seconds.

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Your heart rate varies as the body’s need to absorb oxygen or excrete carbon dioxide changes, such as during exercise or sleep.

USEFUL TIPSYou can use the stop watch running on your wrist watch or mobile phone if it has one.



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Try to increase your heart rate Now do some exercise, such as walking or running on the spot, or stepping up and down stairs, and measure your heart rate again. Was it higher or lower? Your heart rate tends to increase during or after exercise as your body needs more oxygen, and there is more carbon dioxide to excrete.

Elite athletes have heart rates that are significantly lower than those of normal people. For instance, the American cyclist, Lance Armstrong, has a resting heart rate of 32 beats per minute (well below the aver-age of 60-80 beats per minute). The reason for this is that, partly as a result of his intensive train-ing, he has very strong heart.

? KNOWDID YOU

When you breathe in, you create negative pressure (a suction force) in your chest, and the blood is partially sucked from your body into your heart. When your heart is full of blood, the right side pumps blood to your lungs while the left side pumps blood to the rest of your body. Your blood pressure is a measure of the pressure that your heart is applying when it pumps blood through the body.

Next, breathe in deeply and listen to your heart rate again. Then breathe out, and listen. Did you notice that the sound of your heart beat changed slightly? Your heart rate speeds up when you breathe in and slows down when you breathe out. The reason why your heart rate changes when you breathe is because the amount of blood in your heart and the pattern of closing of your two sets of heart valves alters slightly when you breathe in and out.

Breathing plays a very important role in your

blood circulation.



© 2011 MTE Studios

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If you can’t use the real stethoscope, make one yourself out of a flexible rubber or plastic tube. Hold the one end against your ear and press the other end firmly against the skin on the left side of your chest. It won’t work as well as a stetho-scope, but you should be able to hear a faint heart beat.

Alternatively, ask someone else to listen to your heart rate using the cardboard inner tube of a toilet roll. It works nearly as well. In Ibn an-Nafis’ day they used a hollowed-out reed to listen to the heart beat of their patients.

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FROM THE LOWER

BODY

TO THE LOWER

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RIGHT LUNG

LEFTLUNG

HEART

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Understanding how the blood circu-lates through our bodies is a very important medical discovery. We now know that it was made by Ibn an-Nafis over 350 years before Sir William Harvey. It is also interesting to know that the work of the early Greek physician, Galen, would have been lost to the modern world if it had not been translated by Muslim scholars into Arabic from the Greek, as the original Greek books have now all been lost. Later, Galen’s work was translated from Arabic into Latin and then into English so that modern people in the West could read it.

activity 3

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