The Bowman's capsule of a nephron is involved in ultrafiltration. Fig. 1.1 is a diagram of part of a Bowman's capsule and glomerulus. [Figure 1.1] With reference to Fig. 1.1, complete Table 1.1 using the letters A – F. Each letter may be used once, more than once or not at all. Table 1.1 feature glomerular filtrate basement membrane podocyte cell capillary endothelial cell letter

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2021). The mark or mark type is shown in brackets.

1. [1] (a) glomerular filtrate E;
2. [1] (a) basement membrane C;
3. [1] (a) podocyte cells D;
4. [1] (a) capillary endothelial cell A;
5. [1] (b) afferent arteriole, (lumen) wider / has larger diameter, than efferent ;
6. [1] (b) causes high, blood / hydrostatic, pressure in, glomerulus / capillaries;
7. [1] (b) pores / gaps / fenestrations, in capillary endothelium; I holes in cells
8. [1] (b) basement membrane acts as a filter / AW;
9. [1] (b) detail of podocytes ; e.g. finger-like structures / folds / slit pores
10. [1] (b) correct ref. to passage of substances; e.g. basement membrane stops, blood cells / large proteins / molecules above RMM 68 000–70 000 or allows urea / glucose / amino acids / ions / water
11. [1] (b) idea of network of capillaries ;
12. [1] (c)(i) as (mean arterial blood) pressure increases the GFR increases, levels off and increases / AW;
13. [1] (c)(i) (plateau occurs) at 100 cm³ min-1 / between 10 and 20 kPa ;
14. [1] (c)(i) AVP; e.g. plateau is normal or healthy value
15. [1] (c)(ii) kidney, damage / disease / cancer ;
16. [1] (c)(ii) dehydration;
17. [1] (c)(ii) low, blood / hydrostatic, pressure or blood loss ;
18. [1] (c)(ii) AVP; e.g. other (relevant) disease