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Question 18N.3.SL.TZ0.19b

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Date November 2018 Marks available [Maximum mark: 4] Reference code 18N.3.SL.TZ0.19b
Level SL Paper 3 Time zone TZ0
Command term Explain Question number b Adapted from N/A
b.
[Maximum mark: 4]
18N.3.SL.TZ0.19b

The scanning electron micrograph (SEM) shows a cell in the liver responsible for the breakdown of erythrocytes. The cells are found in the lining of the sinusoid walls.

(b)

Explain reasons for the dual blood supply to the liver.

[4]

Markscheme

a. the dual supply is the hepatic artery and the hepatic portal vein ✔
Both needed

b. blood in «hepatic» artery provides oxygen to the liver «tissues» ✔

c. the «hepatic portal» vein carries blood from the gastrointestinal tract/intestines ✔

d. the «hepatic portal» vein carries blood rich in nutrients ✔

e. this allows the nutrients to be stored/processed
OR
sugar/glucose/glycogen is stored and released in response to hormones ✔

f. prevents osmotic imbalance due to absorbed nutrients in the blood ✔

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