| Date | May 2016 | Marks available | 6 | Reference code | 16M.3.HL.TZ0.22 |
| Level | Higher level | Paper | Paper 3 | Time zone | TZ0 |
| Command term | Outline | Question number | 22 | Adapted from | N/A |
Question
Outline the ways in which the liver regulates the chemical and cellular composition of the blood.
Markscheme
Stores glucose as glycogen
OR
Releases glucose from glycogen
Under influence of insulin/glucagon «respectively» depending on blood glucose levels
Some nutrients in excess can be stored in the liver (Accept vitamin A or D stored)
The liver detoxifies blood
OR
The liver removes/breaks down toxins/alcohol/drugs «from the blood»
Kupffer cells engulf bacteria
Kupffer cells breakdown erythrocytes/red blood cells/hemoglobin by phagocytosis
Hemoglobin is split into heme and globin
Iron from heme/hemoglobin breakdown is carried to the bone marrow «to produce new hemoglobin in new red blood cells»
OR
Excess iron stored in liver
Surplus cholesterol is converted to bile salts
OR
Cholesterol is synthesized
«Hepatocytes» produce plasma proteins (Accept specific plasma proteins such as albumin)
Examiners report
Variations on this question have been asked in examinations for the past syllabus so candidates seemed well prepared on the functions of the liver. Many candidates were able to get full marks although often irrelevant material, such as discussion on bile or details of glucose control, was included. Candidates needed to focus on regulation of chemical and cellular composition of the blood and only stronger candidates did both.
