Transport in humans Banker

1. (a) What is the function of platelets?A carrying oxygenB producing antibodiesC helping blood to clotD engulfing bacteria [1]

1. (a) Which part of the blood carries most of the urea from the liver to the kidneys?A plasmaB plateletsC red blood cellsD white blood cells [1]

1. (a) Name the component of blood that:(i) contains haemoglobin(ii) produces antibodies(iii) engulfs and digests bacteria(iv) transports dissolved glucose, hormones and carbon dioxide. [4]
2. (b) State one difference in structure between a red blood cell and a white blood cell. [1]

A blood test report from a laboratory in Karachi for a 16-year-old girl, Ayesha, shows a low haemoglobin level and fewer red blood cells than normal. A normal sample contains about 4 500 000 red blood cells and 7500 white blood cells in each mm³.

1. (a) Calculate how many red blood cells there are for every white blood cell in a normal sample. [1]
2. (b) Ayesha's haemoglobin level is low. Explain why this makes her tired and short of breath when she climbs stairs. [3]
3. (c) Suggest one mineral that should be increased in her diet and name one food that contains it. [2]

1. (a) Describe how a phagocyte destroys a bacterium. [2]
2. (b) Describe how the appearance of a phagocyte and a lymphocyte differ when seen in a stained blood smear. [2]
3. (c) Explain how lymphocytes help to protect the body against a pathogen. [2]

1. (a) Describe how a blood clot forms when the skin is cut. [3]
2. (b) Explain two reasons why clotting is important. [2]
3. (c) Suggest why it is important that fibrinogen is soluble while it is carried in the plasma. [1]

A long-distance runner trained for four weeks at about 2200 m above sea level in the mountains of Gilgit-Baltistan. Her red blood cell count rose from 5.0 million per mm³ to 5.6 million per mm³.

1. (a) Calculate the percentage increase in red blood cell count. [2]
2. (b) There is less oxygen in each breath of air at high altitude. Explain how the change in red blood cell count helps the athlete. [2]
3. (c) Suggest why the athlete performs better in a race at sea level for a few weeks after returning. [2]

1. (a) Which factor increases the risk of coronary heart disease?A eating plenty of fresh vegetablesB regular brisk walkingC a diet high in saturated animal fatD a low intake of salt [1]

1. (a) Describe what happens in the coronary arteries in coronary heart disease. [2]
2. (b) Explain why a blocked coronary artery can cause a heart attack. [3]
3. (c) Give two risk factors for coronary heart disease that a person can change. [2]

A study followed 500 men aged 40–50 in Lahore for ten years. 300 were non-smokers and 200 smoked. Of the non-smokers, 12 developed coronary heart disease. Of the smokers, 22 developed it.

1. (a) Calculate the percentage of non-smokers and of smokers who developed coronary heart disease. [2]
2. (b) Calculate how many times more likely a smoker in this study was to develop the disease than a non-smoker. Give your answer to 2 decimal places. [1]
3. (c) Suggest two reasons why the study cannot prove that smoking causes coronary heart disease. [2]
4. (d) Name one substance in tobacco smoke that increases the risk of coronary heart disease. [1]

A student sat still for 5 minutes and counted his pulse for 15 seconds: 18 beats. He then did step-ups for 3 minutes and counted his pulse for 15 seconds at the start of each minute after stopping.time after exercise / min: 0, 1, 2, 3, 4, 5beats in 15 s: 32, 28, 24, 21, 19, 18

1. (a) Convert each count to a pulse rate in beats per minute. [2]
2. (b) Calculate the percentage increase in pulse rate immediately after exercise compared with rest. Give your answer to 1 decimal place. [2]
3. (c) State how long it took for the pulse rate to return to the resting rate. [1]
4. (d) Explain why the heart beats faster during exercise. [3]
5. (e) Suggest one way to make the pulse measurement more accurate. [1]

1. (a) Explain how a balanced diet and regular exercise can reduce the risk of coronary heart disease. [4]
2. (b) A trained athlete has a resting heart rate of 52 beats per minute; an untrained person of the same age has 74. Suggest why the athlete's heart can supply the body at rest with fewer beats. [2]

1. (a) In which order does blood pass through these structures, starting from the vena cava?A right atrium → right ventricle → pulmonary artery → lungsB left atrium → left ventricle → aorta → lungsC right atrium → right ventricle → pulmonary vein → lungsD right ventricle → right atrium → pulmonary artery → lungs [1]

1. (a) Name the four chambers of the heart. [2]
2. (b) Explain why the wall of the left ventricle is thicker than the wall of the right ventricle. [2]
3. (c) State the function of the septum. [1]
4. (d) Explain why the walls of the atria are thinner than the walls of the ventricles. [1]

1. (a) A doctor listening with a stethoscope hears two sounds in each heartbeat, often written as 'lub-dub'. Explain what causes each sound. [2]
2. (b) Explain the function of the semilunar valves. [2]
3. (c) A patient has a leaking valve between the left atrium and left ventricle. Suggest one effect on the patient and why. [2]

Pressures (in mm Hg) in the left side of the heart and the aorta were measured during one heartbeat.time / s: 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8left atrium: 5, 8, 4, 3, 4, 6, 7, 6, 5left ventricle: 4, 7, 50, 112, 120, 85, 10, 4, 4aorta: 82, 80, 78, 108, 116, 98, 92, 87, 82

1. (a) Using the data, state the times at which the semilunar valve in the aorta is open. Give a reason. [2]
2. (b) State the times at which the valve between the left atrium and left ventricle is closed. [1]
3. (c) One complete cardiac cycle lasts 0.8 s. Calculate the heart rate in beats per minute. [1]
4. (d) Explain why the pressure in the aorta never falls as low as the pressure in the ventricle. [2]

1. (a) Which blood vessel contains valves along its length?A aortaB capillaryC pulmonary arteryD vein in the leg [1]

1. (a) Give three differences between the structure of an artery and a vein. [3]
2. (b) Explain how the thick, elastic wall of an artery is related to its function. [2]

1. (a) Capillary walls are one cell thick. Explain why this is important. [2]
2. (b) The lumen of a capillary is about 8 µm wide and a red blood cell is about 7.5 µm wide. Suggest how this helps oxygen reach the tissues. [2]
3. (c) Explain why most cells in the body are close to a capillary. [2]

A student viewed prepared sections of two blood vessels, X and Y, under a microscope with an eyepiece graticule. At this magnification one graticule unit = 25 µm.vessel X: wall 12 units thick, lumen 40 units acrossvessel Y: wall 4 units thick, lumen 88 units across

1. (a) Calculate the actual wall thickness and lumen diameter of each vessel in mm. [4]
2. (b) Identify which vessel is the artery and which is the vein. Use the results to explain your answer. [2]
3. (c) Suggest why the vein appeared flattened and irregular on the slide while the artery stayed round. [1]

1. (a) Which blood vessel carries oxygenated blood?A pulmonary arteryB pulmonary veinC renal veinD vena cava [1]

1. (a) Explain what is meant by a double circulation. [2]
2. (b) A fish has a single circulation. Explain one advantage of a double circulation to a mammal. [2]
3. (c) Explain why blood going to the lungs is kept at lower pressure than blood going to the body. [1]

1. (a) A glucose molecule is absorbed into a capillary in a villus of the small intestine. Describe the route it takes to reach a muscle in the leg, naming in order each blood vessel and each chamber of the heart. [6]
2. (b) Explain why the glucose molecule must pass through the lungs before it reaches the leg muscle. [1]

1. (a) Plasma transports many substances. Complete each line by naming where the substance is carried from and to.(i) glucose(ii) urea(iii) carbon dioxide(iv) insulin [4]
2. (b) State two other substances carried in plasma. [2]

1. (a) Describe how the structure of a red blood cell is adapted to its function. [4]
2. (b) Explain how haemoglobin picks up oxygen in the lungs and releases it in an actively respiring muscle. [3]

1. (a) Describe the ways in which blood protects the body against infection. [5]
2. (b) A 5.0 cm³ blood sample was spun in a centrifuge. Cells made up 45 % of the volume. Calculate the volume of plasma in cm³. [1]
3. (c) Suggest why the cells sank to the bottom of the tube. [1]

1. (a) Describe how tissue fluid is formed. [2]
2. (b) State two functions of tissue fluid. [2]
3. (c) Describe what happens to the tissue fluid that does not return to the capillaries. [2]

In an adult, about 20 dm³ of fluid leaves the blood capillaries each day to form tissue fluid. About 17 dm³ of this returns directly into the capillaries.

1. (a) Calculate the percentage of the fluid that returns to the blood through the lymphatic system each day. [2]
2. (b) In a disease spread by mosquitoes, small worms block lymph vessels in the legs. The legs become very swollen. Explain why. [2]
3. (c) Lymph passes through lymph nodes. State the function of the lymph nodes. [2]

Mean blood pressure in different vessels (kPa): aorta 13.3; large artery 12.0; capillary 4.0; vein 1.3; vena cava 0.3.

1. (a) Calculate the percentage fall in pressure between the aorta and the capillaries. Give your answer to the nearest whole number. [2]
2. (b) Suggest why it is important that pressure in the capillaries is much lower than in the arteries. [2]
3. (c) Name the blood vessel that carries:(i) blood rich in absorbed food from the small intestine to the liver(ii) blood to the kidney(iii) oxygenated blood from the lungs to the heart. [3]

1. (a) Blood in the veins of the legs must travel upwards to the heart at low pressure. Explain how this happens. [4]
2. (b) A soldier standing still on guard duty for a long time on a hot day may faint. Suggest why. [3]