Question

Choose the correct sequence based on transmission of the sound waves from the outer ear to the brain.

• A. Pinna → tympanic membrane → auditory canal → cochlea → malleus → incus → stapes → auditory nerve
• B. Pinna → malleus → incus → stapes → auditory canal → tympanic membrane → cochlea → auditory nerve
• C. Pinna → auditory canal → tympanic membrane → malleus → incus → stapes → cochlea → auditory nerve
• D. Pinna → cochlea → tympanic membrane → auditory membrane → auditory canal → incus → malleus → stapes → cochlea → auditory nerve

Answer 1

The correct option is C Pinna → auditory canal → tympanic membrane → malleus → incus → stapes → cochlea → auditory nerve

The outer ear consists of the cartilaginous pinna that opens into an external auditory canal which leads inwards. The sound waves travel through the pinna and reach the ear drum. The vibations produced by the ear drum are then, transferred to the three ear ossicles which are present in the middle ear. They, then, reach the oval window. From there, the vibrations are transferred to the cochlea. In response to the vibrations, the hair cells present in the organ of corti in cochlea bend and press themselves against the tectorial membrane. This results in the generation of nerve impulses. These impulses are then, transferred to the auditory cortex of the brain through the auditory nerves.

Therefore, the correct sequence of regions (based on their organisation in the ear as well as based on the transmission of sound waves to the brain) is as given in the option c.