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- 1. AQA AS Physical Education PHED 1 Double Circulatory System Physiology: Structure and function of the heart By the end of this lesson you should be able to: • Describe how the heart is structured in relation to its function as a dual action pump • Explain the events of the cardiac cycle in relation to the conduction system of the heart. Your heart is just part of your cardiovascular system. “Cardio” means heart and “vascular” means the circulatory network of blood vessels. Your cardiovascular system ensures a constant supply of blood to all parts of the body, to help it meet the demands of the body’s tissues. The picture above gives and overview of the cardiovascular system. Heart Facts • Put your hand on your heart. Did you place your hand on the left side of your chest? Many people do, but the heart is actually located almost in the centre of the chest, between the lungs. It's tipped slightly so that a part of it sticks out and taps against the left side of the chest, which is what makes it seem as though it is located there. • Hold out your hand and make a fist. If you're a kid, your heart is about the same size as your fist, and if you're an adult, it's about the same size as two fists. • Your heart beats about 100,000 times in one day and about 35 million times in a year. During an average lifetime, the human heart will beat more than 2.5 billion times. • Give a tennis ball a good, hard squeeze. You're using about the same amount of force your heart uses to pump blood out to the body. Even at rest, the muscles of the heart work hard - twice as hard as the leg muscles of a person sprinting. • Feel your pulse by placing two fingers at pulse points on your neck or wrists. The pulse you feel is blood stopping and starting as it moves through your arteries. As a kid, your resting pulse might range from 90 to 120 beats per minute. As an adult, your pulse rate slows to an average of 72 beats per minute. • The aorta, the largest artery in the body, is almost the diameter of a garden hosepipe. Capillaries, on the other hand, are so small that it takes ten of them to equal the thickness of a human hair. Page 1 of 6
- 2. AQA AS Physical Education PHED 1 Double Circulatory System • Your body has about 5.6 litres of blood. This 5.6 litres of blood circulates through the body three times every minute. In one day, the blood travels a total of 19,000 km (12,000 miles) that's the same as walking from Land’s End to John O’Groats 14 times! • The heart pumps about 1 million barrels of blood during an average lifetime - that's enough to fill more than 3 super tankers. • lub-DUB, lub-DUB, lub-DUB. Sound familiar? If you listen to your heart beat, you'll hear two sounds. These "lub" and "DUB" sounds are made by the heart valves as they open and close Task 1: Using your textbook, page 55, table 4.01, complete the following table identifying the relevant function for the anatomical structure of the heart. Structure of the heart Function Aorta Atria AV bicuspid valve Right ventricle Pulmonary vein Septum Page 2 of 6
- 3. AQA AS Physical Education PHED 1 Double Circulatory System Task 2 Using the words below identify the structures of the heart. Aorta Superior vena cava Bicuspid valve Left atrium Septum Pulmonary vein Inferior vena cava Right ventricle Right atrium Tricuspid valve Pulmonary artery Pulmonary valve Left ventricle Aortic valve Task 3 On the above diagram, colour the arrows blue which represent blood low in oxygen content and red for those representing oxygen-rich blood. Page 3 of 6
- 4. AQA AS Physical Education PHED 1 Double Circulatory System Task 4 Starting at the venae cavae, place the following structures in the correct order that a red blood cell would pass on its journey through the heart. Aorta Left ventricle Right atrium Bicuspid valve Lungs Right ventricle Left atrium Pulmonary artery Tricuspid valve Pulmonary vein 1. Venae cavae____ 5. _______________ 9. ______________ 2. _______________ 6. _______________ 10. _____________ 3. _______________ 7. _______________ 11. _____________ 4. _______________ 8. _______________ Task 5 Watch the clip and read The conduction system of the heart, page 56, and then complete the match up task. Task 6 Now you know what the components are you should be able to identify where in the heart they are. Atrioventricular node (AVN) Bundle of HIS Septum Purkinje (Purkyne) fibres Sinoatrial node (SAN) Page 4 of 6
- 5. AQA AS Physical Education PHED 1 Double Circulatory System Plenary: Gap Fill Page 5 of 6
- 6. AQA AS Physical Education PHED 1 Double Circulatory System Role Play: How does the conduction system work? 1. Identify the component parts you will need to be able to act out the conduction system. 2. Practice your demonstration. Remember you will need to explain what each component is doing. 3. Video yourselves acting out the conduction system Plenary Questions: While you are waiting to video yourselves, or after you have finished you need to work in pairs and to make up 6 questions that cover what you have learned about the structure of the heart and the conduction system: • 2 very easy questions, worth 1 or 2 marks. - In your exam these will usually be questions that ask you to define, state or identify something. - Gaining these points relies on you knowing the glossary terms. • 2 quite difficult questions, worth 2 - 4 marks. - In your exam these will usually be questions that ask you to describe something. - These questions need you to have a good understanding of a topic. • 2 harder questions, usually worth 4 - 7 marks, often having more than one part. - These questions usually ask you to explain something. - This needs you to be able to apply your knowledge to a specific situation. You will find PowerPoints and Useful Links on the VLE. These resources will help you explore this subject. If you take care to complete extra research after each lesson you will increase your ability to achieve higher grades in the exam. Be ready to recap the structure and conduction system at the beginning of the next lesson. Page 6 of 6