Explain what produces this difference in pressure.

Transcription

1 1. The graph below shows the main stages of the cardiac cycle. The atria contract The muscles of the heart relax The thick muscular walls of the ventricles contract (a) During which stage in the cardiac cycle: (i) does the blood flow into the atria? are the atrioventricular valves closed? (b) (i) How would you expect the pressure in the right ventricle to differ from the pressure in the left ventricle? Explain what produces this difference in pressure. (Total 4 marks) The Queen Katherine School 1

2 2. The diagram below shows the arrangement of some blood and lymph vessels. (a) Give one way in which the composition of tissue fluid differs from that of plasma. (b) (i) What is the main function of the lymph vessels? Describe the function of the valves in the lymph vessels. (c) Several conditions can lead to swelling of the ankles and legs. Explain why swelling of the ankles might occur in: (i) a person who is suffering from high blood pressure; a person who has been infected with large numbers of parasitic worms which live in lymph vessels. The Queen Katherine School 2

3 (Total 5 marks) The Queen Katherine School 3

4 3. The table below gives some information about blood vessels in the lung of a mammal. Arteries Capillaries Veins Wall contains a lining layer (endothelium) muscle tissue elastic tissue Total number of vessels 2,400 1,200,000 2,400 Mean length of vessel / mm Diameter 4mm 8µm 5mm Mean rate of blood flow / mm s Less than 1 25 (a) (i) Calculate the total length of capillaries in the lungs. Give your answer in metres. Answer...m Describe and explain two ways in which the information in the table shows that the capillaries in the lungs are adapted for efficient absorption of oxygen (b) What is the importance of elastic tissue in the walls of the arteries? The Queen Katherine School 4

5 4. The diagram shows variations in certain features of blood vessels in different parts of the circulatory system. Elastic fibres Permeability Muscle fibres Aorta Small arteries Arterioles Capillaries Venules Veins (a) Describe the difference in the ratio of elastic fibres to muscle fibres between the aorta and the arterioles. (b) Explain the importance of this ratio in (i) the aorta; the arterioles supplying the skin (c) Explain how the structure of the capillaries is related to their function. (Total 7 marks) The Queen Katherine School 5

6 5. The diagram shows blood capillaries surrounded by tissue cells. X Y (a) (i) Give one difference in composition between blood plasma at X and tissue fluid at Y... Explain what causes this difference... (b) When a person is bitten by a mosquito, the substance histamine is released. Histamine increases the permeability of capillary walls so that large molecules can pass through. Explain how this change in permeability results in swelling round the bite (3) (c) The diameter of a capillary is approximately the same as the diameter of a red blood cell. Explain one way in which this increases the efficiency of the exchange of respiratory gases The Queen Katherine School 6

7 (Total 7 marks) The Queen Katherine School 7

8 6. The diagrams show the left side of the heart at two stages in a cardiac cycle. X Diagram A Diagram B (a) Name the structure labelled X.... (b) Describe two pieces of evidence in Diagram B which indicate that the ventricle is emptying (c) The cardiac output is the volume of blood that one ventricle pumps out per minute. The resting heart rate of an athlete often decreases as a result of training, even though the cardiac output remains the same. Suggest an explanation for this (d) During exercise the rate of blood flow to heart muscle increases from 270 cm 3 per minute to 750 cm 3 per minute. (i) Calculate the percentage increase in rate of blood flow to heart muscle during exercise. Show your working. Answer... % The Queen Katherine School 8

9 Explain the advantage of the increase in the rate of blood flow to heart muscle during exercise. (Total 8 marks) The Queen Katherine School 9

10 7. The table shows the mean thickness of the wall of some mammalian blood vessels. Blood vessell Mean thickness of wall / mm A 0.5 B 2.0 C E 0.03 F 1.0 (a) Which of the blood vessels A to E is (i) a capillary;... the aorta?... (b) The walls of mammalian arterioles have a large amount of muscle. Explain how this muscle can reduce the blood supply to a particular part of the body. (c) The diagrams show the circulatory systems of a mammal and of a fish. Lungs Direction of blood flow Heart Heart Gills Body tissues Body tissues Circulatory system of a mammal Circulatory system of a fish The blood pressure in the arterioles supplying the body tissues is higher in a mammal than in a fish. Use information from the diagram to suggest what causes this. The Queen Katherine School 10

11 (Total 5 marks) The Queen Katherine School 11

12 8. Earthworms have long, thin bodies and live in damp soil. They have no special breathing organs; they simply absorb oxygen directly through the skin. Figure 1 shows part of the blood system in a section across an earthworm. Figure 1 (a) Using information from Figure 1, explain two ways in which the blood vessels in the body wall help the earthworm to absorb oxygen (b) The blood of the earthworm is circulated by five pairs of simple hearts which connect the dorsal and ventral blood vessels. Each heart has muscular walls which contract and contains valves, as shown in Figure 2. Dorsal blood vessel Valve Muscular wall Ventral blood vessel Figure 2 The Queen Katherine School 12

13 Explain how the valves ensure that blood flows in one direction only. (c) The blood of an earthworm contains haemoglobin. Describe how haemoglobin helps the blood of the earthworm to transport oxygen. (d) The lugworm is similar to an earthworm, but lives in seashore mud where there is a very low oxygen concentration. Figure 3 shows the oxygen haemoglobin dissociation curves of the lugworm and the earthworm. 100 Percentage saturation of haemoglobin with oxygen 50 Lugworm Earthworm Partial pressure of oxygen Figure 3 Explain the advantage to the lugworm of having the dissociation curve in the position shown. (Total 8 marks) The Queen Katherine School 13

14 9. The diagram shows the circulatory system of a human in a simplified way. Capillaries in head and arms A B C Capillaries in right lung Capillaries in left lung D V F E Capillaries in abdominal organs Capillaries in legs (a) In the blood vessels in the diagram, add arrows next to the letters, A, B, C and D to show the direction of blood flow at each position. The Queen Katherine School 14

15 (b) Which of the blood vessels, A to F, (i) carries blood with the highest concentration of oxygen;... contains the carotid bodies?... (c) The valve, V, helps to maintain blood flow through the heart. Describe how it carries out this function. (Total 6 marks) The Queen Katherine School 15