The vibrations that produce sound travel through a delicate process before reaching the hair cells in the organ of corti. The process begins with the collection of sound waves by the pinna which then travels down the auditory canal where it reaches the tympanic membrane. Once her the vibrations cause the tympanic membrane to vibrate at he same frequency as the sound. From here the three ossicles bones begin to vibrate and amplify the vibrations. This then causes the oval window to vibrate which also cause the fluid within the cochlea to vibrate. The vibrations are then recieved by the round window and proceed down to the organ of corti where the hair cells bend causing the release of neurotransmitter into the synapses and the message is carried to the brain via the auditory nerve where it is interpreted.
Figure 20.1 Represents the process a sound wave travels in order to be heard but the ear and interpreted by the brain. is the video above which illustrates the path of sound through the ear in order for it to be heard by a human.

Aubusson, Eileen Kennedy Peter. Biology in Context: the Spectrum of Life. Victoria : Oxford Uni. Press., 2001. Print.
"HSC Online." NSW HSC Online. N.p., n.d. Web. 25 June 2010. <>.
"YouTube - Travel Inside the Ear ." YouTube - Broadcast Yourself.. N.p., n.d. Web. 29 June 2010. <>.