O-LevelBiologyTransport in Humans5090/21 · Oct/Nov 2017 · Q213 Marks

Fig. 2.1 shows a section through a human kidney and its associated structures. [Figure 2.1]

(a)(i)Name the blood vessels P and Q in Fig. 2.1. P Q[2]
(a)(ii)Name the fluid R in Fig. 2.1 and describe the route taken by this fluid from leaving the kidney to being removed from the body. name of fluid route taken by fluid[4]
(b)(i)Suggest why the connection made between blood vessels is called an AV fistula.[1]
(b)(ii)State one way in which blood returning from the kidney machine will differ from blood leaving the body to enter the kidney machine.[1]
(c)Describe the role in dialysis of each of these components of a kidney machine: artificial membrane dialysis fluid[5]

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Mark scheme

Marking points from the official mark scheme (Oct/Nov 2017). The mark or mark type is shown in brackets.

[2] (a)(i) P renal artery; Q renal vein;
[4] (a)(ii) urine; ureter; bladder; urethra;
[1] (b)(i) reference to artery + vein ;
[1] (b)(ii) lower pressure ; less/no urea ; reference to increase / decrease + concentration of ions AW ;
[5] (c) (artificial membrane) partially permeable AW ; small molecules or named + pass through (membrane); correct reference to diffusion / osmosis ; proteins do not pass through (membrane); (dialysis fluid) no/low urea OR removes urea ; reference to concentration gradient; same glucose concentration + as normal blood ; same ion AW concentration + as normal blood ;

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