Excretion Banker

1. (a) Which tube carries urine from a kidney to the bladder?A renal veinB urethraC ureterD renal artery [1]

1. (a) Which substance is normally found in the glomerular filtrate but NOT in the urine of a healthy person?A glucoseB saltsC ureaD water [1]

1. (a) Define excretion. [2]
2. (b) Name the organ that excretes carbon dioxide and the organ that excretes urea. [2]
3. (c) Name the tube that carries urine out of the body from the bladder. [1]

1. (a) Name the blood vessel that brings blood to the kidney. [1]
2. (b) Name the three regions seen when a kidney is cut lengthwise, starting from the outside. [3]
3. (c) State where the glomeruli are found. [1]

1. (a) State two substances that are reabsorbed into the blood from the kidney tubules. [2]
2. (b) Name the structure that stores urine. [1]

A sheep kidney was cut lengthwise. It has a dark outer layer (cortex) about 5 mm thick, a paler inner region (medulla) made of cone-shaped pyramids, and a white funnel-shaped space (pelvis) at the concave side, from which the ureter leaves.

1. (a) State which region of the kidney described contains:(i) the glomeruli and Bowman's capsules(ii) the loops of Henle and collecting ducts [2]
2. (b) The actual length of the kidney was 60 mm. A student drew the section 150 mm long. Calculate the magnification of the drawing. [2]

1. (a) State the function of the glomerulus. [1]
2. (b) State the function of the collecting duct. [1]
3. (c) Name the blood vessel that carries filtered blood away from the kidney. [1]

1. (a) Why are proteins absent from the filtrate in the Bowman's capsule?A They are actively absorbed by the glomerulus.B Their molecules are too large to pass through the filter.C They are digested in the kidney.D They are converted to urea in the glomerulus. [1]

Concentrations in g per 100 cm³:substance | blood plasma | filtrate in Bowman's capsule | urinewater | 92 | 98 | 96protein | 7.0 | 0.0 | 0.0glucose | 0.10 | 0.10 | 0.00urea | 0.03 | 0.03 | 2.00salts | 0.72 | 0.72 | 1.50

1. (a) Use the table to name the substance that is not filtered. Explain why. [2]
2. (b) Glucose is present in the filtrate but not in the urine. Name the process responsible and where it happens. [2]
3. (c) Calculate how many times more concentrated urea is in urine than in plasma. Give your answer to 2 significant figures. [2]
4. (d) Explain why urea becomes more concentrated in urine. [1]

1. (a) Describe how filtrate is formed in the glomerulus and Bowman's capsule. [3]
2. (b) State the name of this process. [1]

A healthy adult produces urine at a mean rate of 1.2 cm³ per minute. The urine contains 20 g of urea per dm³.

1. (a) Calculate the mass of urea excreted in one day (24 hours). Give your answer in grams to 3 significant figures. [2]
2. (b) On one day this person's urine gives an orange colour with Benedict's solution. Suggest an explanation. [2]

Artificial urine samples from three patients were tested.sample 1: Benedict's blue; biuret bluesample 2: Benedict's orange; biuret bluesample 3: Benedict's blue; biuret purple

1. (a) Identify which sample is from the person likely to have diabetes. Give a reason. [2]
2. (b) Sample 3 contains protein. Suggest what this shows about the kidneys of person 3. [1]
3. (c) Describe how the biuret test was carried out on the samples. [2]
4. (d) State one safety precaution when testing urine. [1]

1. (a) A man runs a marathon in hot weather in Dubai and drinks little water. Predict how the volume and colour of his urine will change. Explain your answer. [3]
2. (b) Explain why urine is still produced even when the body is short of water. [1]

1. (a) The blood in the renal vein, compared with the blood in the renal artery, hasA less urea and less oxygen.B more urea and less oxygen.C less urea and more oxygen.D more glucose and more oxygen. [1]

In an adult, about 125 cm³ of filtrate passes from the blood into the nephrons every minute.

1. (a) Calculate the volume of filtrate formed per day in dm³. [2]
2. (b) On the same day the person produced 1.5 dm³ of urine. Calculate the percentage of the filtrate that was reabsorbed. Give your answer to 1 decimal place. [2]
3. (c) Suggest why the volume of urine produced is larger on a cool, rainy day than on a hot day. [2]

1. (a) Describe the path of a urea molecule from the renal artery until it leaves the body. [4]
2. (b) Explain why the cells lining the proximal tubule have many mitochondria. [2]

Three volunteers each drank 1 dm³ of water on one day and 1 dm³ of salty soup on another. Urine volume collected in the next 2 hours (cm³):water: 520, 480, 560salty soup: 210, 190, 230

1. (a) Calculate the mean volume of urine for each drink, to 1 decimal place. [2]
2. (b) Explain the difference in mean urine volume. [2]
3. (c) Suggest two variables that should be controlled. [2]

1. (a) Explain how the structure of the glomerulus and Bowman's capsule is adapted for ultrafiltration. [3]
2. (b) A person's blood pressure falls very low. Suggest the effect on filtration and urine production. [2]

1. (a) Where in the body is urea made?A bladderB kidneyC liverD pancreas [1]

1. (a) State what is meant by deamination. [2]
2. (b) State how urea travels from where it is made to the kidneys. [1]

1. (a) Explain why the body cannot store excess amino acids in the same way that it stores excess glucose. [1]
2. (b) A wrestler eats a diet very rich in meat and eggs. Predict how the amount of urea in his urine will change, and explain why. [2]

1. (a) Compare urea and urine. [2]
2. (b) Explain why urea must be removed from the body. [1]
3. (c) After deamination, the remaining part of the amino acid is not wasted. State what happens to it. [1]

A patient with kidney failure had a blood urea concentration of 1.2 g/dm³ before dialysis and 0.1 g/dm³ after.

1. (a) Calculate the percentage decrease in urea in the blood during one dialysis session. Give your answer to 1 decimal place. [2]
2. (b) Explain why the patient's blood urea rises again between sessions. [2]

1. (a) State why the dialysis fluid contains no urea. [1]
2. (b) State why the dialysis membrane must be partially permeable. [1]
3. (c) Give two reasons why dialysis is less convenient for patients than having a kidney transplant. [2]

1. (a) Why does the dialysis fluid used in a kidney machine contain glucose at the same concentration as normal blood?A so that glucose diffuses into the bloodB so that glucose is not lost from the blood by diffusionC so that urea can diffuse into the bloodD so that the fluid gives the patient energy [1]

1. (a) Explain how a dialysis machine removes urea while keeping glucose and useful salts in the blood. [4]
2. (b) Calculate how many hours a patient spends on dialysis in one year if each session is 4 hours, three times a week. [1]

1. (a) Describe the processes that take place in a nephron to produce urine from blood plasma. [5]

A person in Jacobabad, one of the hottest cities in Pakistan, produces about 0.8 dm³ of urine a day in June but 1.6 dm³ in January.

1. (a) Explain why the person needs to drink more water in the hot season to keep the same urine output. [2]
2. (b) Kidney stones can block a ureter. Suggest two effects of a complete blockage of one ureter. [2]
3. (c) Explain why drinking plenty of water is advised for people likely to form kidney stones. [1]

1. (a) State one advantage of a kidney transplant compared with dialysis. [1]
2. (b) State two problems with kidney transplants. [2]

1. (a) Explain why a kidney from a close relative is more likely to be successful than one from an unrelated donor. [2]
2. (b) Patients take drugs that suppress the immune system after a transplant. Explain one disadvantage of this. [2]