Which is transmission of sound vibrations to the internal ear?

RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Applied Physiology

Easy

Appeared in: RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Explanation

The tympanic membrane (eardrum) is a thin, cone-shaped membrane that separates the external ear from the middle ear.
When sound waves travel down the external auditory canal and strike the tympanic membrane, it vibrates.
This action converts the energy of the sound waves into mechanical vibrations.
These vibrations are then transferred to the three tiny bones in the middle ear (ossicles), which is the crucial first step in transmitting the sound to the internal ear.

Option A: The auricle (or pinna) is the external part of the ear. Its function is to collect and funnel sound waves into the ear canal, not to transmit vibrations to the internal ear.
Option C: The vestibule is a component of the internal ear itself, specifically the bony labyrinth. It contains the utricle and saccule, which are organs of balance (static equilibrium). It receives vibrations but does not transmit them to the internal ear.
Option D: The Eustachian tube (or auditory tube) connects the middle ear to the back of the throat (nasopharynx). Its primary role is to equalize air pressure on both sides of the tympanic membrane, allowing it to vibrate freely. It does not transmit sound vibrations for hearing.

Visual 1: Diagram - A cross-section of the human ear (outer, middle, and inner). This visual should clearly label the auricle, external auditory canal, tympanic membrane, ossicles (malleus, incus, stapes), Eustachian tube, vestibule, and cochlea to illustrate the complete pathway of sound.
Visual 2: Animation - A short animation showing a sound wave entering the ear, causing the tympanic membrane to vibrate, the ossicles to move, and the fluid in the cochlea to be stimulated. This helps in understanding the dynamic process of sound transmission.

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.
Understanding the function of the tympanic membrane is crucial for diagnosing and managing conditions like otitis media (middle ear infection), where fluid buildup can dampen vibrations and cause hearing loss.
A perforated or ruptured tympanic membrane, caused by infection, trauma, or sudden pressure changes, directly impairs the transmission of sound, leading to conductive hearing loss. Nurses must educate patients on protecting their ears.
What if? - If a patient has otosclerosis, a condition where the stapes bone becomes fixed and cannot vibrate properly, the transmission of sound from the tympanic membrane to the inner ear is severely impaired, even if the tympanic membrane itself is healthy. This results in significant conductive hearing loss.

How to Approach the Question

First, identify the core concept of the question, which is the 'transmission of sound vibrations to the internal ear'.
Mentally trace the path of sound through the ear: Sound is collected by the outer ear, converted to vibrations in the middle ear, and then processed in the inner ear.
Evaluate each option based on its specific role in this pathway.
Option A (Auricle) is for collection. Option B (Tympanic membrane) is for converting sound to vibrations. Option C (Vestibule) is part of the destination (inner ear) and is for balance. Option D (Eustachian tube) is for pressure equalization.
Conclude that the tympanic membrane is the structure that initiates the mechanical transmission of vibrations that will eventually reach the internal ear.

Concept Tested & Keywords

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