Question 19N.3.SL.TZ0.5
| Date | November 2019 | Marks available | [Maximum mark: 6] | Reference code | 19N.3.SL.TZ0.5 |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Explain, Identify, Suggest | Question number | 5 | Adapted from | N/A |
The MRI brain scans show the cerebral hemispheres of two people of the same age, one of whom is suffering from multiple sclerosis and has lost motor functions.
[Source: © Frontiers in Bioscience. Role of MRI in Multiple Sclerosis II: Brain and Spinal
Cord Atrophy, Robert Zivadinov and Rohit Bakshi, 9, 647–664, January 1, 2004]
Identify the structures found at I, II and III.
I:
II:
III:
[2]
a. I: skull bone/cranium ✔
b. II: «left cerebral» hemisphere
OR
III: «right cerebral» hemisphere ✔
Suggest one way in which multiple sclerosis has affected the cerebral hemispheres of the brain.
[1]
less white matter
OR
bigger space in the middle/ventricles
OR
overall area/volume of cortex/cerebrum is reduced/space between cortex/cerebrum and cranium bigger/number of folds is reduced
OR
slower nerve transmission
OR
fewer synapses
OR
function of cerebral hemispheres diminished ✔
The folding of the cerebral hemispheres is extensive and varies between different mammals. Explain briefly the importance of folding of the cerebral hemispheres in humans.
[3]
a. the cerebral hemispheres are responsible for higher order functions ✔
b. the folding permits an increased surface area without increasing the cranium size
OR
permits high surface area to volume ratio ✔
c. increased surface/volume permits more synapses ✔
d. humans have a highly developed/highly folded cerebral cortex ✔
e. folding decreases distances therefore faster communication ✔