| Date | May 2012 | Marks available | 3 | Reference code | 12M.3.SL.TZ2.14 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Explain | Question number | 14 | Adapted from | N/A |
Question
Label the diagram of the ear.
Explain how the cochlea functions during hearing.
Markscheme
Award [1] for any two of the following correctly identified.
I. pinna;
II. bones of the middle ear/ossicles/malleus, incus and stapes;
III. auditory nerve;
IV. cochlea;
bone/ossicle/stapes contacts oval window of cochlea;
ossicle vibrations are transmitted to cochlear fluid via the oval window;
cochlear fluid vibrations cause movement of (basilar) membrane (in precise areas);
movement depends on membrane width and thickness in specific area;
movement causes shearing motion of hair bundles projecting from hair cells attached to membrane;
stimulated hair cells generate action potential that arrive in the brain via auditory nerve;
Examiners report
E2 (c) was well answered.
E2 (d) was answered in very vague terms; there was a lack of biological language.
