Date | May 2019 | Marks available | 2 | Reference code | 19M.3.HL.TZ1.7 |
Level | Higher level | Paper | Paper 3 | Time zone | Time zone 1 |
Command term | Outline | Question number | 7 | Adapted from | N/A |
Question
The diagram shows a section through the human brain.
[Source: https://pixabay.com/vectors/brain-anatomy-human-medicine-150935/]
Label the diagram to show part of the visual cortex of the brain.
Outline how the diagram can be identified as a human brain and not the brain of a monkey.
Explain how studies of lesions have helped to identify the functions of different parts of the brain.
Markscheme
[Source: https://pixabay.com/vectors/brain-anatomy-human-medicine-150935/]
Accept any label within marked area
a. the cerebral hemispheres are larger «relative to rest of brain» ✔
b. the cerebral cortex forms a larger proportion of the brain ✔
c. there is extensive folding of the cerebral cortex ✔
a. lesions are areas of brain injury ✔
b. diagnosed in living people using MRI/CAT scan/PET scan ✔
c. autopsies reveal the position and extent of lesions
OR
animal experimentation ✔
d. the behaviour/functioning of patient with lesion was observed ✔
Other possible techniques: cerebral arteriogram/angiogram, diffusion weighted MRI
Examiners report
Many candidates identified the correct region of the brain.
Few candidates were able to demonstrate the subject-specific vocabulary required to answer this question with clarity. Most did not refer to the cerebral cortex or even cerebrum, instead using vague terms like “brain.” Where students added detail, it was often about the frontal lobe, something this question was not addressing.
Students who did poorly on this question showed the same weaknesses already mentioned in earlier questions. They were unable to define what a lesion was, and few attempted to address the question directly. Rather than explaining how studies of lesions have helped identify functions of the brain, many candidates only described the relationship between parts of the brain and their functions. Nevertheless, a lenient interpretation of the marking point regarding observed changes in patients’ behaviours due to lesions in the brain allowed many students to achieve 1 mark.