'A' Level Medical Option Questions - The Ear
The diagram shows a vertical section through the human ear. Solid bone is shaded grey.
Name and state the function of the parts labelled A, B, C and D.
A: ear drum [or tympanic membrane]
It transfers sound waves from the outer ear to the ossicles of the middle ear
B: ossicles [or bones of the middle ear]
They are a system of levers with a mechanical advantage (of 1.5) [or amplification]
OR which links two membranes (ear drum and oval window) or transmits sound vibrations from outer to inner ear]
C: windows: oval and round
These allow sound vibrations to enter the fluid of the inner ear
OR allow sound vibrations to be transmitted around the cochlea
OR contain the inner ear's fluid while allowing the fluid to move
This converts (pressure) waves [or vibrations] in the fluid into electrical signals
OR stimulates (auditory) nerves to send signals to the brain
(Total 8 marks)
(Total 10 marks)