The Heart and Cardiac Cycle Question Booklet Name………………………………….….. Target Grade………………….. Grade achieved………………. __/62 __% Unit 1- Woodford County High School 1. The diagram shows a human heart (a) On the diagram, label the position of the atrioventricular node. (1) An electro-cardiogram (ECG) is produced by placing electrodes on the chest to detect electrical changes in the heart. The diagram shows an ECG and the pressure changes during a human cardiac cycle. Pressure in aorta Blood pressure Pressure in left ventricle R T P P ECG Q 0 S 0.1 Unit 1- Woodford County High School 0.2 0.3 0.4 Time/seconds 0.5 0.6 0.7 0.8 (b) (i) The QRS wave is associated with the spread of electrical activity over the ventricle. Explain the evidence in the graph which supports this. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (ii) Explain why there is no change in the electrical activity between 0.31s and 0.77s. .......................................................................................................................... .......................................................................................................................... (1) (c) (i) At what time in the cardiac cycle does the aortic semilunar valve open? .......................................................................................................................... (1) (ii) The pressure changes shown in the diagram are on the left side of the heart. Sketch a curve on the graph to show the pressure changes in the right ventricle. (2) (Total 7 marks) 2. The cardiac output is the amount of blood one ventricle pumps out per minute. The table shows the percentage of the cardiac output distributed to various organs when the body is at rest. Organ Percentage of cardiac output at rest Bone 5 Brain 15 Heart 5 Kidneys 25 Liver 15 Skin 5 Unit 1- Woodford County High School (i) At rest the amount of blood pumped out by a single contraction of one ventricle is 70 cm3 and the mean heart rate is 72 beats per minute. Calculate the total volume of blood supplied to the brain per minute. Show your working. Answer = .......................... (2) (ii) Prolonged training often results in a decrease in the resting heart rate although the cardiac output remains the same. How is this decrease achieved? ......................................................................................................................... ......................................................................................................................... (1) (Total 3 marks) 3. (a) During a cardiac cycle, a wave of electrical activity spreads from the sino-atrial node. Describe how the spread of this wave of electrical activity results in (i) the ventricles only contracting after they have filled with blood; .......................................................................................................................... .......................................................................................................................... (1) (ii) the contraction of the ventricles starting at the apex of the heart. .......................................................................................................................... .......................................................................................................................... (1) Unit 1- Woodford County High School (b) The graphs show some of the pressure and volume changes that take place in the left side of the heart during part of a cardiac cycle. 16 14 Key 12 Pressure/kPa Aorta Left ventricle Left atrium 10 8 6 4 2 0 Time 130 120 Volume of left ventricle/cm 3 110 100 90 80 70 60 A B Time Using information from the graphs, describe the events which produce the change in volume of blood in the ventricle between times A and B. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (3) (Total 5 mark) Unit 1- Woodford County High School 4. a) The diagram shows a human heart. Left atrium Coronary artery (i) Use a guideline and label to show the position of the sinoatrial node (SAN). (1) (ii) What is the function of the coronary artery? ......................................................................................................................... (1) (b) Impulses spread through the walls of the heart from the SAN. The table shows the rate of conduction of impulses through various parts of the conducting tissues. Rate of conduction / m s–1 Mean distance / mm From SAN to atrioventricular node (AVN) across atrium 1.0 40 Through AVN 0.05 5 From AVN to lower end of bundle of His 1.0 10 Along Purkyne fibres in ventricle walls 4.0 – Part of pathway Unit 1- Woodford County High School (i) Calculate the mean time taken for an impulse to pass from the SAN to the lower end of the bundle of His. Show your working. ................................... s (2) (ii) Explain the advantage of the slow rate of conduction through the AVN. ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... (2) (iii) Suggest one advantage of the high rate of conduction in the Purkyne fibres which carry impulses through the walls of the ventricles. ......................................................................................................................... ......................................................................................................................... (1) (c) How would cutting the nerve connections from the brain to the SAN affect the beating of the heart? .................................................................................................................................. ................................................................................................................................... (1) (Total 8 marks) Unit 1- Woodford County High School 5. (a) The graph shows the changes in pressure which take place in the left side of the heart. 15 Aorta 10 Pressure/ kPa Left ventricle 5 Left atrium 0 0.2 (i) 0.4 0.6 Time/seconds 0.8 1.0 Use the graph to calculate the heart rate in beats per minute. Show your working. Answer .............................. (2) (ii) The atrioventricular valve closes at 0.1 seconds. Explain the evidence from the graph which supports this statement. ......................................................................................................................... (1) (b) The blood pressure in the aorta is higher than in the pulmonary artery. Explain what causes the blood pressure in the aorta to be higher. ................................................................................................................................... ................................................................................................................................... (1) (Total 4 marks) Unit 1- Woodford County High School 6. The diagram shows the pathways in the heart for the conduction of electrical impulses during the cardiac cycle. (a) The table shows the blood pressure in the left atrium, the left ventricle and the aorta at different times during part of a cardiac cycle. Blood pressure / kPa (i) Time / s Left atrium Left ventricle Aorta 0.0 0.5 0.4 10.6 0.1 1.2 0.7 10.6 0.2 0.3 6.7 10.6 0.3 0.4 17.3 16.0 0.4 0.8 8.0 12.0 At which time is blood flowing into the aorta? ......................................................................................................................… (1) (ii) Between which times are the atrioventricular valves closed? ......................................................................................................................… (1) (b) The maximum pressure in the left ventricle is higher than the maximum pressure in the right ventricle. What causes this difference in pressure? ................................................................................................................................... (1) (Total 3marks) Unit 1- Woodford County High School 7. Although the heart does have a nerve supply, the role of the nervous system is not to initiate the heartbeat but rather to modify the rate of contraction. The heart determines its own regular contraction. Describe how the regular contraction of the atria and ventricles is initiated and coordinated by the heart itself. .................................................................................................................................. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... (5) 8. (a)During the cardiac cycle the heart fills with blood and then the ventricles contract. The table gives the filling time and the contraction time at different heart rates. (i) Heart rate/beats per minute Filling time/seconds Contraction time/seconds 39.7 0.37 1.14 49.6 0.38 0.83 71.4 0.38 0.46 81.1 0.38 0.36 87.0 0.39 0.30 Give two conclusions that can be drawn from the figures in the table. 1 ............................................................................................................... ......................................................................................................................... 2 ...............................................................................................................(2) Unit 1- Woodford County High School (ii) Explain how you would use the figures in the table to calculate the contraction time at a heart rate of 60 beats per minute. ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... (2) (iii) What additional information would you need in order to find the cardiac output at a particular heart rate? ......................................................................................................................... (1) (b) The diagram shows variations in blood pressure in different parts of the circulatory system. Left ventricle A Aorta Vein B Pressure Time (i) Time Time Complete the table with ticks to show whether each of the valves is open or closed at the point indicated with the letter A on the diagram. (2) Valve located between left atrium and left ventricle left ventricle and aorta right atrium and right ventricle right ventricle and pulmonary artery Unit 1- Woodford County High School Open Closed (ii) A pulse can be felt when the fingers are placed over an artery that is close to the surface. Explain why a pulse cannot be felt when the fingers are placed over a vein which is close to the surface. ......................................................................................................................... ......................................................................................................................... (1) (iii) What causes the blood pressure to increase at the point indicated with a letter B on the diagram? ......................................................................................................................... ......................................................................................................................... (1) (Total 9 marks) 9. The diagram shows a section through a human heart. C B A D (a) Which of the blood vessels labelled A to D (i) takes blood from the heart to the muscles of the arms and legs; ........................................................................................................................ (1) (ii) is a vein which contains oxygenated blood? ......................................................................................................................... (1) Unit 1- Woodford County High School (b) Is the right ventricle filling with blood or emptying? Give two pieces of evidence from the diagram to support your answer. Filling or emptying? .................................................................................................. Evidence 1 ......................................................................................................................... 2 ......................................................................................................................... (2) The graphs show some changes in pressure and volume during part of a cardiac cycle. Aorta Pressure Ventricle Volume of ventricle X (c) Y Time Z Describe what the graphs show about the pressure and volume in the ventricle between times X and Y. ................................................................................................................................... ...............................................................................................................................(1) Unit 1- Woodford County High School (d) At point Y, the valve between the aorta and the ventricle opens. Use the information about pressure on the graph to explain why. .................................................................................................................................. ................................................................................................................................... (1) (e) Explain the changes in the volume of the ventricle between times X and Z. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... (3) (Total 9 marks) 10. The graph shows changes in the volume of blood in the left ventricle. 140 120 100 Volume / cm 3 80 60 40 20 0 0 0.2 0.4 0.6 Time / s Unit 1- Woodford County High School 0.8 1.0 (a) Between which times is the left atrium contracting? Give the evidence from the graph that supports your answer. Times ......................................................................................................................... Evidence ……............................................................................................................. ............………............................................................................................................. (2) (b) Use the graph to calculate. (i) the heart rate; Answer ............................................ (2) (ii) stroke volume. Answer ............................................ (1) (c) Describe how you would calculate cardiac output from heart rate and stroke volume. ............……….............................................................................................................. ............……….............................................................................................................. (1) The table shows the rate of blood flow to some organs when a person is at rest and during a period of vigorous exercise. Organ Rate of blood flow / cm3 minute–1 at rest (d) during exercise Skeletal muscles 1 000 16 000 Kidney 1 200 1 200 Brain 750 Heart muscle 300 1 200 Suggest a value for the rate of blood flow to the brain during exercise. ............……….............................................................................................................. (1) Unit 1- Woodford County High School (e) (i) The coronary arteries take blood to the muscles in the wall of the heart. Calculate the ratio of the rate of blood flow into the coronary arteries during exercise to the rate flowing into these arteries at rest. Answer............................................. (1) (ii) At rest the rate of flow of blood to the heart muscle is 0.9 cm3 g–1 per minute. Calculate the volume of blood 1g of heart muscle would receive in 5 minutes of vigorous exercise. Answer............................................. (1) (Total 9 marks) Unit 1- Woodford County High School Mark Scheme 1. (a) correct position of AVN; (at the top of Purkyne tissue) (b) (i) pressure in ventricles increasing (so ventricle contracting); QRS occurs before pressure increase/ventricle contraction/ contracts after S / 0.14s; 2 (ii) corresponds to time when heart is relaxed/filling with blood/ diastole / not contracting; 1 (i) 0.2s ; (ii) line below left ventricle; in phase with left ventricle; 2 (c) 1 1 [7] 2. (a) (i) 70 x 72 = 5040 plus method shown for calculating percentage; 756cm3; 2 (ii) (increase in size of heart) increasing amount of blood pumped out / Increasing stroke volume; 1 [3] 3. (a) (b) (i) Delay in spread of electrical activity at AV node/from atria to ventricle; (ii) Rapid spread of activity down ventricular septum/to base of ventricles/ along bundle of His/electrical activity travels up from base; 1 1 Ventricle contracts/systole; Pressure increases in ventricle/pressure in ventricle higher than in aorta; Valve between ventricle and aorta opens; 3 [5] 4. (a) (b) (i) guideline to upper part of right atrium; (ii) supply oxygen / nutrients to heart muscle / for contraction; (i) 0.15s = 2 marks; (working 0.04 + 0.10 + 0.01 = 1 mark) (allow 1 mark for correct method dividing each distance by rate) (ii) (iii) (c) delays contraction of ventricles; until after atria have contracted / ventricles filled; 1 2 rapid contraction of ventricles / both ventricles contract together / rapid transmission to tip so contraction starts at bottom of ventricles; (reject strong contraction) 1 rate of heart beat not adjusted to activity / carries on beating at Unit 1- Woodford County High School 1 2 constant rate / myogenic, so no effect; (Accept: rate would increase because parasympathetic normally inhibits) 1 [8] 5. (a) (i) (ii) (b) 60 ÷ 0.72 – 0.76; 79 – 83; (Correct answer = 2 marks) 2 Ventricular pressure increases above pressure in atrium ; 1 Left ventricle has thicker / more muscle; 1 [4] 6. (a) (b) (i) 0.3 s; 1 (ii) 0.2 - 0.4 s; 1 thicker / more muscle in the left ventricle; 1 [3] 10. 7. 8. (cardiac) muscle is myogenic; sinoatrial node/SAN; wave of depolarisation/impulses/electrical activity (across atria); initiates contraction of atria atrioventricular node/AVN; bundle of His/purkyne tissue spreads impulse across ventricles; ventricles contract after atria/time delay enables ventricles to fill; (a) (i) (ii) Filling time stays constant / increases very little / as heart rate increases; Decrease in contraction time as heart rate increases; Allow maximum of 1 mark if no reference to heart rate. Work out time for one heart beat / one heart beat takes 1 second; Subtract filling time / 0.38s; Credit these basic points however determined. If the calculation has been done, credit any point in method clearly explained. OR Plot contraction time against heart rate; Unit 1- Woodford County High School [5] 2 (iii) (b) Read off value for 60 beats per minute; 2 Stroke volume / volume of blood pumped out at each beat; 1 (i) 2 Valve located between Open Closed Left atrium and left ventricle Left ventricle and aorta ; Right atrium and right ventricle Right ventricle and pulmonary artery (ii) (iii) ; Pressure constant / smooth in vein / only have pressure surges in artery; 1 Contraction of ventricle / systole / entry of blood into aorta; 1 [9] 9. (a) (b) (i) B/aorta; 1 (ii) D/pulmonary vein; 1 Filling because valve between artery and ventricle closed; Valve between atrium and ventricle/ cuspid valve open; 2 [Note: All answers must be in context of filling. Answers specifically relating to left side are incorrect.] (c) Pressure increases and volume stays constant; (d) Pressure in ventricle (becomes) higher than pressure in aorta; [Or converse] (e) 1 1 ventricle contracts; Produces increase in pressure; Blood leaves venticle/ goes into aorta (and volume falls); Through open valve; max 3 [9] Unit 1- Woodford County High School 10. (a) (b) 0.1 – 0.6 seconds; Volume (in left ventricle) increasing / ventricle filling; (i) (ii) 2 2 marks for correct answer of 75 (beats) per minute; 1 mark if heart beat correctly identified as lasting 0.8 seconds; 2 70 cm ; 1 (c) Multiply them; 1 (d) 750; Accept a small increase – up to 800 cm 1 (e) (i) 4 : 1 / 4; Ratio must be expressed in simplest terms 1 (ii) 18 cm ; 1 [9] Total marks …………………..[62] Unit 1- Woodford County High School
© Copyright 2024 Paperzz