H4 Functions of the liver – summary of mark schemes
H.4.1
Outline the circulation of blood through liver tissue, including the hepatic artery, hepatic portal vein, sinusoids and hepatic vein.
Mark Schemes
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
H.4.3
(oxygenated) blood from heart to liver via hepatic artery;
hepatic artery from aorta brings blood to liver;
hepatic portal vein (from gut) brings blood to the liver;
incoming blood flows merge in sinusoids of liver;
sinusoids are liver capillaries;
sinusoids merge to form hepatic vein;
hepatic vein carries blood away from liver to vena cava;
hepatic artery (carries O2) into liver;
(nutrient laden) blood carried from intestines through hepatic portal vein;
artery / hepatic portal vein divide (eventually) into sinusoids;
sinusoids drain into (branches of) hepatic vein;
blood leaving the liver departs through the hepatic vein;
Outline the role of the liver in the storage of nutrients, including carbohydrate, iron, vitamin A and vitamin D.
Mark Schemes
A.
B.
C.
H.4.6
liver stores excess glucose as glycogen / releases glucose from glycogen (as levels drop);
liver breaks down red blood cells / hemoglobin and stores iron;
liver stores fat soluble vitamins / vitamin A / vitamin D / vitamin B12 / folic acid;
Describe the process of erythrocyte and hemoglobin breakdown in the liver, including phagocytosis, digestion of globin and bile
pigment formation.
Mark Schemes
A.
B.
C.
D.
E.
F.
G.
erythrocytes rupture when they reach the end of their life span / after 120 days;
absorbed by phagocytosis / Kupffer cells in liver from blood;
Kupffer cells found lining sinusoids in liver;
hemoglobin split into globin and heme groups;
iron removed from heme leaving bile pigment / bilirubin;
bilirubin released into alimentary canal;
digestion of globin to produce amino acids;