Which part's function is transmission of sound vibrations to the internal ear?

RRB Nsg. Superintendent-20 July 2019 (Shift-3rd)

Applied Physiology

Easy

Appeared in: RRB Nsg. Superintendent-20 July 2019 (Shift-3rd)

Explanation

The tympanic membrane (eardrum) is positioned at the end of the ear canal and separates the outer ear from the middle ear.
When sound waves travel down the ear canal, they strike the tympanic membrane, causing it to vibrate.
These vibrations are then transferred to the three tiny bones in the middle ear (ossicles), which amplify the sound and transmit it to the inner ear.
This makes the tympanic membrane a critical link in the chain of hearing, converting airborne sound into mechanical energy.

Option A: The Eustachian tube's primary function is to equalize air pressure between the middle ear and the atmosphere, not to transmit sound vibrations.
Option B: The vestibule is part of the inner ear's vestibular system, which is responsible for balance and spatial orientation, not for the transmission of sound vibrations.
Option D: The auricle (or pinna) is the visible part of the outer ear. Its function is to collect and funnel sound waves into the ear canal, but it does not transmit vibrations to the internal ear.

Visual 1: Diagram - A cross-section of the human ear (outer, middle, and inner). The diagram should clearly label the auricle, ear canal, tympanic membrane, ossicles, Eustachian tube, vestibule, and cochlea, with an arrow showing the path of sound.
Visual 2: Animation - A short animation demonstrating how sound waves cause the tympanic membrane to vibrate, and how these vibrations are passed through the ossicles to the cochlea.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy and Physiology of the Ear as background academic context rather than a clinical decision trigger.
A perforated tympanic membrane (a hole in the eardrum) can cause hearing loss because it disrupts the normal transmission of sound vibrations. It can be caused by infection (otitis media), trauma, or sudden pressure changes.
Nurses often assess the tympanic membrane using an otoscope to check for signs of infection, inflammation, or perforation, which are common in conditions like acute otitis media.
What if the Eustachian tube is blocked (e.g., due to a cold or allergies)? This would prevent pressure equalization, causing the tympanic membrane to retract or bulge. This stiffness impairs its ability to vibrate freely, leading to muffled hearing and a feeling of fullness in the ear.

How to Approach the Question

First, identify the key function described in the question: 'transmission of sound vibrations to the internal ear'.
Mentally trace the path of sound through the ear: Sound is collected by the auricle, travels down the ear canal, and hits the tympanic membrane.
Evaluate the function of each option in this pathway.
The tympanic membrane vibrates and passes the energy to the middle ear bones (ossicles), which then connect to the inner ear. This matches the question's requirement.
Eliminate the other options based on their primary functions: Eustachian tube (pressure), Vestibule (balance), and Auricle (collecting sound).

Concept Tested & Keywords

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