Question

Describe the pathway of sound from the ear to the cochlea. Describe two types of deafness that can occur and how are they treated. How do we localize the source of a sound?

Answer 1

1. Sound waves from the external source will enter the ear through the external part. The sound enters in the form of vibrating wages. These waves are carried by the eardrum to the middle ear. The middle ear consist of three small bones such as the malleus, incus and stapes. These bones will help in amplifying or increasing the strength of sound stimuli received and is passed on to cochlea which is present in the inner ear.

The two main types of deafness are sensorineural hearing loss and conductive hearing loss. Sensorineural hearing loss is associated with damage to either inner ear or auditory or a combination of both. The main causes for the same include genetic factors, aging and constant exposure to extremely loud noise beyond normal dB for a prolonged time. Treatment includes using of hearing aids.

Conductive hearing loss is associated with damage to the external or middle ear structures. The causes for the same include trauma, wax impaction and stenosis of the ear drum carrying sound to middle ear. Treatments includes surgical removal of wax, use of antibiotics etc.

Source of sound is one that is localized based on the part of eardrum that vibrates close to the source. If the source is close or nearby, internal part vibrates strong while a distant source will lead to vibration of external part of the eardrum