Question

The part of the ear where sound is transduced is (a) tympanic membrane (b) ear ossides (c) semicircular canals (d) cochlea.

Short answer

The part of the ear where sound is transduced is (d) cochlea.

Step-by-step solution

Understand the Function of Each Option

To determine where sound is transduced, understand the function of each part of the ear listed. The tympanic membrane (a) vibrates in response to sound waves. The ear ossicles (b) are small bones that amplify these vibrations. The semicircular canals (c) are involved in balance. The cochlea (d) is a fluid-filled structure that contains the sensory cells for hearing.

Identify the Part Where Transduction Occurs

Transduction of sound occurs when mechanical energy from sound waves is converted into electrical signals by sensory cells. This happens in the cochlea, where hair cells line the organ of Corti and transduce mechanical vibrations into electrical signals sent to the brain.

Select the Correct Option

Based on the functions, the correct part of the ear where sound is transduced is the cochlea. Therefore, the correct answer is (d) cochlea.

Key concepts

Cochlea Function

The cochlea is a critical component in the complex process of hearing. It resembles a snail shell and is filled with fluid. When sound waves travel through the ear canal, they eventually reach the cochlea after being amplified by the ear ossicles. Inside this spiral structure are tiny hair cells that line the organ of Corti. These sensory cells move in response to the fluid's vibrations, triggering an impressive transduction process.

As the fluid inside the cochlea moves, it bends the hair cells, causing them to release neurotransmitters. These chemical messengers excite the auditory nerve fibers, converting mechanical vibrations into electrical impulses. The auditory nerve then carries these impulses to the brain, where they are interpreted as sound. This elegant transformation from airborne vibrations to electrical signals allows us to perceive and interpret an array of sounds.

Sensory Cells for Hearing

The sensory cells for hearing, often referred to as hair cells, are meticulously organized inside the cochlea. There are two types of hair cells: outer and inner. The outer hair cells amplify the sound vibrations and fine-tune the frequency sensitivity, enhancing our ability to discern sounds at different pitches. The inner hair cells convert these vibrations into electrical signals.

The process is intricately sensitive, allowing for the wide range of hearing capabilities that humans possess. Damage to these cells, however, cannot be repaired, which is why exposure to loud noises can lead to permanent hearing loss. Understanding how these sensory cells operate is crucial for both appreciating the mechanics of hearing and for developing strategies to protect our hearing health.

Mechanics of Hearing

The mechanics of hearing involve a series of steps that convert sound waves in the air into signals that our brains can understand. It begins when sound waves enter the ear canal and strike the tympanic membrane, commonly known as the eardrum. This membrane vibrates in sympathy with the incoming sound waves.

These vibrations are then transferred to the three tiny bones of the middle ear known as the ossicles. Their names—the malleus, incus, and stapes—are less important than their role: they act as levers to amplify the vibrations and transmit them to the oval window, which is the entrance to the cochlea. In the cochlea, the real magic happens as the vibrations are transduced by the sensory cells. This intricate ballet of movement and energy conversion across different media—air, solid, and fluid—enables us to hear a symphony, a conversation, or the subtlest of whispers.