Mechanism of Hearing: Anatomy, FAQs

What Is Hearing? (Definition)

The mechanism of hearing is one of the complex processes by which the sound waves get converted into electrical signals that the brain interprets as sound. This process forms the basis of communication and environmental awareness.

Collection of Sound Waves (Outer Ear)

Hearing initiates by collecting sound waves through the outer ear.

Role of Pinna

• Collects sound waves

• Directs them into external ear canal

Ear Canal

• Conducts sound waves to ear drum

Transmission of Sound Waves (Middle Ear)

It is responsible for pressure wave transmissions and amplifies the pressure waves in the air.

Eardrum (Tympanic Membrane)

• The eardrum vibrates with the arrival of sound waves.

• The vibrations then get passed on to the ossicles.

Ossicles (Malleus → Incus → Stapes)

• The ossicles amplify the vibrations

• Deliver mechanical energy to inner ear

Conversion of Vibrations into Electrical Signals (Inner Ear)

In the inner ear, the sound waves get changed into electrical signals.

Cochlea

• The cochlea has hair cells.

• These turn the vibration of the sound into a nerve impulse.

Transmission of Signals to Brain

These nerve impulses are then passed on to the brain, which interprets them.

Auditory Nerve:

• It carries the electrical impulses from the cochlea to the brain.

Mechanism of Hearing Diagram NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Structure of the human ear

• Mechanism of hearing and equilibrium

Practice Questions for NEET

Q1. Which of the following statements accurately describes the structure of the ear with regard to sound transmission?

1. The ear ossicles significantly enhance the efficacy of sound wave propagation.

2. The malleus is connected to the oval window.

3. The Eustachian tube establishes a connection between the middle ear cavity and the larynx.

4. The middle ear is composed of three ear ossicles known as malleus, incus and sphenoid.

Correct answer: 1) The ear ossicles significantly enhance the efficacy of sound wave propagation.

Explanation:

The ear ossicles, which include the malleus, incus, and stapes, play a crucial role in enhancing the efficiency of sound wave transmission. These tiny bones located in the middle ear amplify and transmit sound vibrations from the tympanic membrane (eardrum) to the oval window, a membrane-covered opening in the cochlea. By mechanically amplifying the sound waves, the ear ossicles increase the effectiveness of sound transmission into the fluid-filled inner ear.

Hence, the correct answer is option 1) The ear ossicles significantly enhance the efficacy of sound wave propagation.

Q2. The external ear receives sound waves and directs them to the

1. Basilar membrane

2. Eardrum

3. Ossicles

4. Auditory cortex

Correct answer: 1) Eardrum

Explanation:

Sound waves are received by the external ear and sent to the tympanic membrane (eardrum). The external auditory canal, which directs sound waves toward the tympanic membrane before sending them to the middle ear for additional processing, and the pinna, the visible portion of the ear, make up the external ear.

Hence, the correct answer is option 2) Eardrum.

Q3. Assertion: The vibrations are then passed to 3 tiny bones in the middle ear called the ossicles. The ossicles amplify the sound.

Reason: When a sound is made outside the outer ear, the sound waves, or vibrations, travel down the external auditory canal and strike the eardrum (tympanic membrane). The eardrum vibrates.

1. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark A

2. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark B

3. If the Assertion is a true statement but the Reason is false, then mark C

4. If both Assertion and Reason are false statements, then mark D

Correct answer: 1) If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark A

Explanation:

Both Assertion & Reason are true and the reason is the correct explanation of the assertion. When a sound is made outside the outer ear, the sound waves, or vibrations, travel down the external auditory canal and strike the eardrum (tympanic membrane). The eardrum vibrates. The vibrations are then passed to 3 tiny bones in the middle ear called the ossicles. The ossicles amplify the sound. They send the sound waves to the inner ear and into the fluid-filled hearing organ (cochlea). Once the sound waves reach the inner ear, they are converted into electrical impulses. The auditory nerve sends these impulses to the brain. The brain then translates these electrical impulses as sound.

Hence, the correct answer is option 1) both Assertion & Reason are true and the reason is the correct explanation of the assertion.

Also Read:

• MCQs on Mechanism of Hearing

• Action Potential

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