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Question 1
The diagram below shows a cross section of a kidney. |
a) | Name structures X and Y in the diagram above.
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b) | The formation of urine involves the processes of ultrafiltration and selective reabsorption. Where in the kidneys does the process of ultrafiltration occur?
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c) | Describe the process of ultrafiltration.
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d) | Selective reabsorption occurs in the proximal convoluted tubule. Give two ways in which the cells of the proximal convoluted tubule are adapted for this process.
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Question 2
The diagram below shows the structure of a nephron in a kidney.
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a) | Give the letters from the diagram above that are found in the cortex of the kidney.
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b) | On the diagram, draw a box around the loop of Henle.
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c) | Explain the role of the loop of Henle in reabsorption of water from the filtrate.
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d) | Some desert mammals have longer loops of Henle compared to animals that do not live in desert conditions. Explain how this feature is an adaptation to their environment.
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Question 3
The body contains osmoreceptors that respond to changes in the water potential of the blood. |
a) | When the body is dehydrated, the volume of an osmoreceptor cell decreases. Explain why.
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b) | Stimulation of osmoreceptors may lead to the secretion of antidiuretic hormone (ADH). Name the part of the body that secretes ADH.
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c) | ADH is released when the body is dehydrated. Explain how ADH affects the urine produced by the kidneys.
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d) | Some desert mammals secrete large amounts of ADH. Explain how this is an adaptation to their environment.
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Question 4
The diagram below shows a glomerulus in which the process of ultrafiltration takes place. |
a) | Name three substances that would be present in the glomerular filtrate.
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b) | Explain how the glomerulus is able to carry out its function.
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c) | The processes of ultrafiltration and the formation of tissue fluid both occur in the capillaries. Give three other similarities between ultrafiltration and the formation of tissue fluid.
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d) | Give two differences between ultrafiltration and the formation of tissue fluid.
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Question 5
Mammalian kidneys are responsible for removing urea from the blood. |
a) | Describe how urea is removed from the blood of a mammal.
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b) | Explain how urea becomes concentrated in the filtrate.
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c) | Kidney failure can occur when the kidneys become unable to filter waste products from the blood. This results in high levels of urea within the blood. Suggest two other effects that kidney failure has on the composition of the blood.
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Question 6
Mammals contain specialised cells that can detect changes to the water potential of the blood. |
a) | Name the type of specialised cell that detects changes in blood water potential and state their location in the body.
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b) | Alcohol inhibits the release of antidiuretic hormone (ADH), causing an increase in the volume of urine. Suggest two other signs or symptoms which may result from the inhibition of ADH.
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c) | Explain why the inhibition of ADH causes an increase in the volume of urine.
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Question 7
Diabetes is a condition that affects the control of blood glucose concentration. |
a) | Explain why the urine of a person without diabetes does not contain any glucose.
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b) | Type 1 diabetes is caused by a lack of the hormone insulin. Explain why glucose is found in the urine of a patient with untreated diabetes.
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c) | Suggest and explain why patients with untreated diabetes produce a larger volume of urine.
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d) | High blood glucose concentrations can damage the small blood vessels in the kidneys, leading to proteins from the blood plasma collecting in the urine. Which part of a nephron would be damaged to cause this effect? Explain your answer.
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Question 8
The diagram below shows how the concentration of filtrate changes as it passes through the kidney tubule. |
a) | Describe and explain how the filtrate concentration changes as it passes through the proximal convoluted tubule.
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b) | Describe and explain how filtrate concentration changes as it passes through the loop of Henle.
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c) | Describe the evidence from the diagram above that antidiuretic hormone (ADH) was being secreted.
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d) | A species of crayfish lives in freshwater. In order to survive in this environment, the crayfish produces large amounts of dilute urine. Suggest how this behaviour allows the crayfish to survive.
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