Date | November 2018 | Marks available | 6 | Reference code | 18N.3.HL.TZ0.8 |
Level | Higher level | Paper | Paper 3 | Time zone | TZ0 / no time zone |
Command term | Explain | Question number | 8 | Adapted from | N/A |
Question
Explain how the eye detects stimuli and sends information to the brain.
Markscheme
a. photoreceptors/cones/rods detect «reflected» light/stimulus ✔
b. cones found in fovea «of retina» and rods found all over retina ✔
c. rods active in low-intensity/dim light ✔
d. cones active in high-intensity/bright light ✔
e. rods give black and white vision ✔
OWTTE
f. cones detect colours ✔
OWTTE
g. bipolar neurons/cells synapse with multiple rods but «only» with individual cones ✔
OWTTE
h. bipolar neurons/cells «in the retina» form synapses with ganglion cells ✔
i. electrical/nerve impulses travel to brain/occipital lobe via the optic nerve ✔
j. right field of vision from both eyes sent to the left part of the visual cortex through the chiasma «and vice versa» ✔
Allow answers in annotated diagrams