Kidney

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1.

An investigation was carried out into the reabsorption of water from the nephrons in human kidneys. The total volume of filtrate produced by the glomeruli in the kidneys was 180 dm3 per day. The table below shows the volumes of water which were reabsorbed from this filtrate in different regions of the nephrons. Volume of water reabsorbed / dm3 per day 147.0 10.0 19.2 to 19.5 2.2 to 2.7

Region of nephrons

Proximal convoluted tubules Loops of Henl Distal convoluted tubules Collecting ducts (a)

Calculate the maximum volume of urine produced per day. Show your working.

Answer .(2)

(b)

(i) tubule.

Describe how water is reabsorbed from the proximal convoluted

... ... ... ... ... ...(3)

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(ii)

Explain why the volume of water reabsorbed in the distal convoluted tubules and collecting ducts is variable. ... ... ... ... ... ...(3)

(c)

Explain how the nephrons of desert mammals are adapted to increase conservation of water. .. .. .. .. .. ..(3) (Total 11 marks)

2.

The diagrams below are from different regions of a mammalian kidney and show transverse sections of proximal convoluted tubules, distal convoluted tubules and loops of Henl.

(a)

Identify the region of the kidney shown in diagram A, giving a reason for your answer. . . . .(2)

(b)

(i) The tissue was stained during the preparation of the sections. The cells of the proximal convoluted tubules stained more densely than those of the distal convoluted tubules because they contained a greater density of organelles. Explain this difference in density of organelles in terms of the functions of the proximal convoluted tubule. ... ... ... ... ... ...(3)

(ii)

State two ways, shown in the diagrams and other than the dense staining of the cytoplasm of the cells, in which the proximal convoluted tubules differ from the distal convoluted tubules. 1 ... ... 2 ... ...(2)

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(c)

(i)

State the function of the loop of Henl.

... ...(1)

(ii)

Describe the role of the descending limb of the loop of Henl. ... ... ... ...(2) (Total 10 marks)

3.

An investigation was carried out to assess the effect of changes in the salt concentration of the blood upon the rate of production of urine. A small sample of salt solution was injected into the carotid artery carrying blood up to the head of a mammal. The rate of urine production following the injection was monitored for the next 40 minutes. The results of the investigation are shown in the table below. Time after injection / min 0 5 10 15 20 25 30 35 40 Rate of urine production / cm3 min1 7.0 1.1 0.6 1.0 1.5 2.2 2.4 3.1 4.2

(a)

Describe the effect of the injection of salt solution on the rate of urine production. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(3)

(b)

Explain why the injection had this effect. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(4)

(c)

The investigation was repeated by injecting a small sample of the salt solution into the jugular vein carrying blood back from the head of the mammal. No change in the rate of urine production was detected. Suggest a reason for this. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(2) (Total 9 marks)

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4.

Describe the following processes which occur during urine formation in mammals. (a) Ultrafiltration .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(2)

(b)

Selective reabsorption of glucose .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(2) (Total 4 marks)

5.

The diagram below shows the simplified structure of a kidney tubule (nephron).

(a)

In the table below, columns 1 and 2 show the quantities of water, glucose and urea passing through P and Q in a 24 hour period. Column 3 and 4 show the quantities and percentages reabsorbed during the same period.

Complete the table by writing the correct figures in the boxes labelled (i) to (iv). Q u a n t i t Q y u a n t i Qt y u a n t i P t y e r c e n t a g e s t a n p c a e s s i n g p a s s i n r g e a b s o r r b e ea db s o r b e d Q t h r o u g ht h Pr o u g h a t e r 1 l u U c o s e1 5 8 8 3 0 0 g d g m 1 . 5 d m 1 7 1 2 5 g( i i i )

S W G

u

b

8 8 0

. 5 g

( i )

d

m 1

0 0

( i i )

r e a

( i v

)

(4)

(b)

Describe how R is involved in adjusting the concentration of the filtrate as it passes through the medulla of the kidney. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(3) (Total 7 marks)

6.

The graph below shows how the rates of filtration and reabsorption of glucose in human nephrons vary with concentration of glucose in the blood plasma. 4

3 R a t e o f f i l t r a t i o o r r e a b s o r p t i o n o f g l u c 2o s e / m m o 1 l m i n n K F R e y i l t r a t i o n e a b s o r p r a t e t i o n r a t e

1

0

0

1

0

2

0

3

0 o a f

4 /

0 g m l u m c o o s e l d m

C o n c e n t r a t i o n i n b l o o d p l a s3 m

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(a)

(i)

From the graph determine the maximum rate of glucose reabsorption.(1)

.......................................................................................................................... (ii) Comment on the relationship between filtration rate and reabsorption rate as shown by these two curves. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................(3)

(b)

If the concentration of glucose in the blood plasma exceeds 20 mmol dm3, glucose appears in the urine. Suggest an explanation for this observation. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(2)

(c)

(i)

State where in the nephron glucose is reabsorbed.(1)

.......................................................................................................................... (ii) Describe how glucose is reabsorbed. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................(2)

(iii)

Name two other substances which are reabsorbed in the same part of the nephron as glucose. 1 ..................................................................................................................... 2 .....................................................................................................................(2) (Total 11 mark)

7.

Diabetes insipidus is a condition in which large volumes of dilute urine are produced. The volume of urine produced each day by a patient with diabetes insipidus was recorded. On certain days the patient received an injection of pituitary extract. The results are shown in the table below. The asterisks (*) indicate the days on which pituitary extract was injected. D 1 2 3 4 5 6 7 8 (a) * a y V o l u 5 6 5 5 7 5 1 2 m . 4 . 0 . 8 . 0 . 0 . 7 . 9 . 2 1 1 1 1 1 e3o

f

u

r i n De / a d y m V 9 0

o

l u 6 4 5 5

m . 3 . 9 . 1 . 5 . 5 . 1 . 4 . 7

e

3o

f

u

r i n

e / d

m

1 1 1 3 4 5 6 2 * * * *

1 2 2 1

Describe the effect of the injection of pituitary extract on the volume of urine produced each day. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(2)

(b)

Name the substance responsible for this effect. ....................................................................................................................................(1)

(c)

Describe how this effect is brought about. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................(2) (Total 5 marks)

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8.

Read through the following account of kidney function, then write on the dotted lines the most appropriate word or words to complete the account. In the kidney, the renal artery branches to form many smaller arterioles, each of which divides further to form a knot of capillaries called a ............................................... Here, small molecules such as..................................and ................................................are forced into the cavity of the Bowmans (renal) capsule by process of....................................................Selective reabsorption takes place in the nephron. In the proximal convoluted tubule all the....................................................is reabsorbed. In the ascending limb of the loop of Henl, ions are actively pumped out of the nephron. This causes..................................................to be drawn out of the collecting duct.(Total 6 marks)

9.

The table below shows the average concentrations of four substances, urea, glucose, sodium ions and potassium ions, in different regions of the kidney tubule (nephron). The figures are expressed as g dm Concentration of substance / g dm3 Substance Bowmans capsule 0.3 0.1 0.33 0.17 Proximal convoluted tubule 0.55 0 0.33 0.02 Distal convoluted tubule 6 0 0.1 0.06 15 0 0.33 0.85 Collecting duct

Urea Glucose Sodium ions Potassium ions (a)

Large volumes of water are reabsorbed into the blood from the proximal convoluted tubule. Suggest why the concentration of sodium ions remains unchanged but the concentration of urea increases.(2)

(b)

(i) Calculate the percentage change in the concentration of urea between the beginning and the end of the tubule. Show your working.(2)

(ii)

Suggest a reason for the change in the concentration of urea in the distal convoluted tubule and the collecting duct.(1)

(c)

Comment on the changes in the concentration of sodium ions and potassium ions in the distal convoluted tubule and collecting duct.(2)

(d)

The concentration of glucose falls to 0 in the proximal convoluted tubule. Explain how this is brought about.(2)

(e)

The diagram below shows a section through a cell wall of the proximal convoluted tubule of a kidney nephron.

(i)

Name the features X and Y on the diagram of the cell from the proximal convoluted tubule and indicate their significance in the process you described in (d). X .. Significance .(2)

Y ... Significance ..(2)

(ii)

Name two structures other than those labelled X and Y which indicate that this is a eukaryotic cell. 1 2 (2) (Total 15 marks)

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10.

An investigation was carried out into the reabsorption of water from the nephrons in human kidneys. The total volume of filtrate produced by the glomeruli in the kidneys was 180 dm3 per day. The table below shows the volumes of water which were reabsorbed from this filtrate in different regions of the nephrons. Volume of water reabsorbed / dm3 per day 147.0 10.0 19.2 to 19.5 2.2 to 2.7

Region of nephrons

Proximal convoluted tubules Loops of Henl Distal convoluted tubules Collecting ducts (a)

Calculate the maximum volume of urine produced per day. Show your working.

Answer .(2)

(b)

(i) tubule.

Describe how water is reabsorbed from the proximal convoluted

... ... ... ... ... ...(3)

(ii)

Explain why the volume of water reabsorbed in the distal convoluted tubules and collecting ducts is variable. ... ... ... ... ... ...(3) (Total 8 marks)

11.

Write an essay on the following topic. Production and elimination of metabolic waste products in humans(20 marks)

12.

An investigation was carried out to determine the quantities of water, glucose and urea passing through different parts of kidney nephrons in 24 hours. The results are shown in the table below. Substance Quantity passing through Bowmans capsules 190 dm3 180 g 53 g Quantity passing through collecting ducts 1.5 dm3 0.0 g 25 g 100 52.8 Percentage reabsorbed

Water Glucose Urea (a)

Calculate the percentage reabsorption of water. Show your working.

Answer ....................................................................(2)

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(b)

Explain how each of the following substances is reabsorbed from the proximal convoluted tubule of the nephron. (i) glucose ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................(3)

(ii)

water ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................(3)

(c)

Suggest a reason why some urea is reabsorbed by the nephron. ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. .................................................................................................................................(2) (Total 10 marks)

13.

The diagram below represents a kidney tubule (nephron). A

B D

C

(a)

Name the parts labelled A, B, C and D. A ................................................................................................................................. B ................................................................................................................................. C ................................................................................................................................. D .................................................................................................................................(2)

(b)

The concentration of urea was measured in the parts of the nephron labelled A, B and D. Part of nephron A B D Concentration of urea / g dm3 0.30 0.55 6.0-7.0

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(i)

Explain how the change in the urea concentration between part A and part B is brought about. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................(2)

(ii)

Explain why the urea concentration in part D of the nephron may vary at different times during the day. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................(3)

(c)

When this person ate a high protein diet, the urea concentration in part A of the nephron was 0.36 g dm3. (i) Calculate the percentage change in the urea concentration in part A resulting from this change in diet.

Answer..............................................(3)

(ii)

Give an explanation for this change in urea concentration. ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................ ............................................................................................................................(3) (Total 13 marks)

14.

(a) The formation of the mammalian excretory product urea can be summarised by the following word equation. Ammonia + Carbon dioxide Urea + Water (i) Name the organ in which urea is formed. ..........................................................................................................................(1)

(ii)

State how the ammonia is produced. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................(2)

(iii)

Suggest how the carbon dioxide used in the formation of urea is produced. .......................................................................................................................... ..........................................................................................................................(1)

(b)

In an investigation, a student compared the concentration of urea in her urine before and after taking a drink of water. The student measured the concentration of urea in urine samples for a period of 5 days. Each day she took a urine sample within 15 minutes of waking after a nights sleep. She then drank 0.75 dm3 water. A second urine sample was then taken 30 minutes after drinking the water.

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The results of this investigation are shown in the table. Urea concentration before drinking / mol dm3 1.1 1.3 1.1 1.0 1.5 1.2 Urea concentration after drinking / mol dm3 0.2 0.3 0.3 0.1 0.3 0.2

Day 1 2 3 4 5 Mean

(i)

Calculate the mean percentage change in the urea concentration as a result of taking the drink of water. Show your working.

Answer ..............................................................(2)

(ii)

Explain how drinking the water may have caused the reduction in urea concentration in the urine. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................(4)

(iii)

Suggest why an estimate of the urea concentration in urine is not a reliable estimate of the total solute concentration of the urine. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................(2) (Total 12 marks)

15.

The diagram shows part of a nephron from a mammalian kidney. B lo o d e n te r in g v ia a ffe re n t a rte rio le

G lo m e ru lu s

C a v ity o f re n a l ( B o w m a n 's ) c a p s u le

B lo o d le a v in g v ia e ffe re n t a rte rio le

F iltr a te p a s s in g to re s t o f n e p h ro n (a) Name the region of the kidney in which the renal capsules are found. .(1)

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(b)

Describe and explain the process of ultrafiltration. . . . . . . . .(4)

(c)

Name one substance, filtered from the blood, that would be completely reabsorbed as the filtrate passes through the nephron. .(1) (Total 6 marks)

16.

An investigation was carried out into the effect of antidiuretic hormone (ADH) on urine production in a mammal. The rate of urine production was measured over a period of 30 minutes. Five minutes after measurements began, ADH was injected into a vein of the mammal. The results are shown in the graph below. I n 5 j e c t i o n o f A D H

R a t e o f u r i n e 4 p r o d u c t i o n / c3 m 1 m i n 3

2

1

0

0

5

1

0

1

5

2

0

2 T

5 i m e

3

0 /

m

i n

(a)

Name the gland that releases ADH. ......................................................................................................................................(1)

(b)

Describe the effect of the injection of ADH on the rate of urine production in the mammal in this investigation. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ......................................................................................................................................(3)

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(c)

Describe the mechanism by which ADH produces the effect seen in this investigation. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... .......................................................................................................................................(4)

(d)

In a similar investigation, an injection of sodium chloride (salt) solution was given after five minutes instead of ADH. This injection was observed to affect urine production in a similar way to ADH. Suggest how the sodium chloride brought about this effect. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... .......................................................................................................................................(3) (Total 11 marks)

17.

Give an account of the structure of the kidney. (Allow two lined pages).(Total 8 marks)

18.

The diagram below shows the loop of Henle from a nephron in the mammalian kidney. The numbers on the diagram show changes in the relative concentration of solutes in the filtrate as it passes through this part of the nephron. D ir e c tio n o f flo w o f filtr a te 100

300

D e s c e n d in g lim b 500 300

A s c e n d in g lim b

900

700

1200 (a) (i) Explain how, in the ascending limb, the relative concentration of solutes in the filtrate changes from 700 to 100. ... ... ... ...(3)

(ii)

Explain how, in the descending limb and the base of the loop, the relative concentration changes from 300 to 1200. ... ... ... ...(3)

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(b)

The ability of the nephron to reabsorb water from the filtrate is important in maintaining the water balance of the body. Describe how the concentration changes in the loop of Henl assist in water reabsorption from the filtrate back into the body. ....... ....... ....... .......(2) (Total 8 marks)