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Question 1
The diagram below shows a cross-section of an artery. |
a) | Explain why an artery is classified as an organ.
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b) | Name the layer labelled A in the diagram above.
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c) | The artery wall contains elastic tissue. Explain the advantage of this.
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d) | Capillaries are another type of blood vessel found in the circulatory system. Describe one way in which the structure of the artery wall is similar to the structure of a capillary wall.
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e) | Describe and explain four features of capillaries that enable efficient exchange of substances between the blood and surrounding tissues.
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Question 2
Tissue fluid is formed from blood plasma. |
a) | Describe and explain one way in which the composition of tissue fluid is different to the composition of blood plasma.
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b) | Describe the role of the heart in the formation of tissue fluid.
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c) | Explain how water from tissue fluid is returned to the circulatory system.
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d) | A high concentration of salt in the blood plasma can cause salt to enter the capillaries. Explain how this can lead to a build-up of tissue fluid.
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Question 3
The diagram below shows part of the human circulatory system. |
a) | Name blood vessels labelled A and B in the diagram above.
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b) | Describe the pathway taken by a red blood cell through the human circulatory system from a kidney to the lungs.
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c) | Blood moves in one direction as it travels though the heart. Describe two features that allow a unidirectional flow of blood inside the heart.
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d) | Some blood vessels not shown in the diagram above are the coronary arteries. What is the role of the coronary arteries?
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Question 4
Arteries and veins are both types of blood vessels found in the human circulatory system. |
a) | Describe how the structure of an artery is adapted for its function.
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b) | Describe three differences between the structure of a vein and an artery.
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c) | Explain why veins have a different structure to arteries.
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d) | Explain how one feature of the capillaries allows them to carry out efficient gas exchange.
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Question 5
A student investigated how surface area to volume ratio affected the rate of diffusion. She used two agar cubes containing an indicator and placed them in hydrochloric acid. She timed how long it took for each cube to change colour. Cube A was cut so that each side was 10 mm in length, whereas cube B was cut so that each side was 2 mm in length. |
a) | State two variables the student should have controlled in this investigation.
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b) | Calculate the surface area to volume ratio for cubes A and B.
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c) | Which cube would you expect to have a greater rate of diffusion? Explain why.
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d) | Explain why animals need specialised transport systems.
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Question 6
A ventricular septal defect (VSD) is a hole in the septum of the heart. The diagram below shows a heart with VSD. |
a) | Name structures labelled A and B in the diagram above.
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b) | Describe the functions of parts A and B in the diagram above.
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c) | Describe the stages of the cardiac cycle in a healthy heart after it has been filled with blood. You do not need to talk about pressure changes within the heart.
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d) | Explain why people with VSD often become easily tired.
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Question 7
The diagram below shows the pressure in the ventricles and the blood flow into the aorta from the heart of a cat. |
a) | Use the diagram to calculate the heart rate of the cat in beats per minute.
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b) | Use the diagram to explain how an increase in ventricle pressure affects the blood flow into the aorta.
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c) | Use the diagram to describe how a decrease in ventricle pressure affects the blood flow into the aorta.
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d) | Explain how muscle tissue and valves in the heart maintain a unidirectional flow of blood from the left atrium to the aorta.
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Question 8
The table below shows how the pressure changes in the left atrium and ventricle at different times during one cardiac cycle. |
a) | Between which times is the atrioventricular valve closed? Explain your answer.
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b) | Use the table to calculate the heat rate in beats per minute.
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c) | The maximum pressure in the ventricle is higher than the maximum pressure in the atrium. Explain why.
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d) | The heartbeat is responsible for bringing deoxygenated blood from around the body back to the heart. Explain how blood in a vein in the arm is returned to the heart.
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Question 9
The diagram below shows a capillary surrounded by tissue fluid. |
a) | Explain how fluid leaves the capillary at the arteriole end.
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b) | Explain why the hydrostatic pressure falls as the blood flows from the arteriole end to the venule end.
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c) | Explain why the water potential of the blood plasma is more negative at the venule end of the capillary compared to the arteriole end.
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d) | Lymphoedema is a swelling in the legs that is often caused by a blockage in the lymphatic system. Suggest how a blockage in this system could cause lymphoedema.
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Question 10
The diagram below shows an ECG trace of a human. The equation for working out cardiac output is as follows: cardiac output = stroke volume x heart rate |
a) | Calculate the cardiac output for this individual with a stroke volume of 80 cm3. Include units in your answer.
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b) | The heart is described as being myogenic. What does this mean?
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c) | Suggest why people who exercise regularly often have a reduced heart rate.
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d) | Describe how the heartbeat is initiated and coordinated.
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