Date | November 2019 | Marks available | 3 | Reference code | 19N.3.SL.TZ0.6 |
Level | Standard level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
Command term | Explain | Question number | 6 | Adapted from | N/A |
Question
The diagram shows part of a human retina.
[Source: reprinted by permission from Springer Nature: Nature Reviews Neuroscience Parallel processing in
the mammalian retina, Heinz Wässle, 2004, Nat Rev Neurosci 5, 747–757 (2004) doi:10.1038/nrn1497]
On the diagram, draw an arrow showing the direction of the light.
Identify the cells labelled A and B.
A:
B:
Explain, using the diagram, how the visual stimuli from the right eye reach the visual cortex of the brain.
Markscheme
[Source: reprinted by permission from Springer Nature: Nature Reviews Neuroscience
Parallel processing in the mammalian retina, Heinz Wässle, 2004,
Nat Rev Neurosci 5, 747–757 (2004) doi:10.1038/nrn1497]
Accept any arrow pointing upwards
A: bipolar cell
B: ganglion cell ✔
Both required
a. right eye receives information/stimuli/light from both «left and right» visual field ✔
b. light from the left visual field goes to the right side of the retina
OR
vice versa ✔
c. impulses «from retina» carried along the optic nerve ✔
d. «optic» nerves cross at «optic» chiasma ✔
e. impulses from the left side of the retina goes to the left side of the brain
OR
vice versa ✔
Accept any of these points made on an annotated diagram.