DESCRIBE THE ANATOMY AND FUNCTION OF THE HUMAN EAR, INCLUDING: PINNA, TYMPANIC MEMBRANE, EAR OSSICLES, OVAL WINDOW, ROUND WINDOW, COCHLEA, ORGAN OF CORTI AND AUDITORY NERVE
The human ear is divided into three sections, the outer, middle and inner ear and plays an important role in hearing. The outer ear consists of the pinna (auricle) that leads into the external auditory canal. It collects sound waves from a wide area and funnels the sound into the external ear passage. On the inside surface of the outer ear is the tympanic membrane (eardrum). It is stretched across the end of the auditory canal separating the outer ear from the middle ear.

The middle ear consists of small bones called ossicles. They are the malleus (hammer), the incus (anvil) and the stapes (stirrup). They transfer sound waves to the inner ear. Located covering an opening into the inner ear is called the oval window. Below is another membrane called the round window that stretches across the opening and adjoins the cochlea in the inner ear.

The inner ear comprises a coiled structure called the cochlea. The snail-like spiral coiled tube contains the receptors for sound and the vestibular apparatus that is associated with a sense of balance. The cochlear duct contains the organ of Corti, which contains auditory receptor cells. The auditory nerve transmits sound vibrations to the brain.



This video explains the structures of the human ear, as well as the function of each structures, therefore making it a reliable video.
(Ear Model (2009) [Online], available form Internet on June 8: http://www.youtube.com/watch?v=XvfHEXooG4U)

the-human-ear.gif
This image of the human ear effectively illustrates the named structures of the human ear which enable hearing.
(The Human Ear (2009) [Online], available from Internet on June 8: http://mail.pittsfield.net/teachersites/Whelihan_Kathleen/0147FF93-000F6E5A.2/The-Human-Ear.gif)

OUTLINE THE ROLE OF THE EUSTACHIAN TUBE
The Eustachian tube leads to the pharynx (chamber located at the back of the mouth or throat region). It is usually closed however can be opened upon swallowing or yawning. The role of the Eustachian tube is to equalize the pressure of either sides of the tympanic membrane.
hwhb17_013_003.jpg
This image effectively shows the detailed structure of the Eustachian tube which has the role to equalise the pressure of either sides of the tympanic membrane.
(Eustachian Tube (2009) [Online], available from Internet on June 8: http://myhealth.ucsd.edu/library/healthguide/en-us/images/media/medical/hw/hwhb17_013_003.jpg)

OUTLINE THE PATH OF A SOUND WAVE THROUGH THE EXTERNAL, MIDDLE AND INNER EAR AND IDENTIFY TRANSFORMATIONS THAT OCCUR
The ear converts the energy of sound waves into pressure waves. These are transferred into nerve impulses that travel to the brain. The sound waves are collected by the pinna and travel down the auditory canal, resulting in the tympanic membrane to vibrate at the same frequency as the entering sound waves. The three ossicles in the middle ear vibrate which transfer vibrations towards the oval window. By the vibrating ossicles, a pressure wave in the fluids of the cochlea is produced. The pressure waves travels through the fluids and the round window membrane is pushed in the opposite direction. This acts as a pressure release valves. The pressure wave in the cochlear fluids moves through the vestibular canal to the tympanic canal. Fluid pressures then push onto the cochlear duct and on the membranes near the organ of Corti. The hair cells of the organ of Corti detect the vibration and pass a message to the brain via the auditory nerve.


Bibliography

Peter Aubusson, Eileen Kennedy, Peter Hickman (2004) Biology in Context The Spectrum of Life Second Edition, Oxford University Press, Victoria

The Human Ear (1996-2007) [Online], available from Internet on June 7: http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/sound/u11l2d.html