Problem 126 - Objective Biology for NEET

Question

In the internal ear, the organ of Corti which bears hair cells is located in (a) Sacculus (b) Scala media (c) Scala tympani (d) Scala vestibuli

Step-by-Step Solution

Answer

The organ of Corti, which contains the hair cells, is located in the Scala media. The correct answer is (b) Scala media.

Step 1: Identify the Organ of Corti

The Organ of Corti is a structure in the cochlea that is essential for hearing. It supports the hair cells that respond to fluid movement in the inner ear and transmit the information to auditory nerve fibers.

Step 2: Understand the Terminology

Sacculus, Scala media, Scala tympani, and Scala vestibuli refer to specific structures within the inner ear.

Step 3: Locate the Organ of Corti

The organ of Corti is housed within the cochlea and it specifically resides in the Scala media.

Key Concepts

Hair Cells

In the inner ear's intricate design, hair cells play a crucial role. These specialized cells are sensory receptors located in the organ of Corti. Hair cells are responsible for converting sound vibrations into electrical signals that the brain can interpret as sound.
Each hair cell contains tiny hair-like structures called stereocilia. When sound waves cause fluid in the cochlea to move, this fluid motion bends the stereocilia.
This bending leads to the opening of ion channels and a subsequent electrical signal transmission to the auditory nerve.

• There are two types of hair cells: inner and outer hair cells.
• Inner hair cells are primarily responsible for sending sound information to the brain.
• Outer hair cells help to amplify and fine-tune sound vibrations.

Understanding hair cells' function is essential in grasping how we perceive sound and identify potential hearing damage causes.

Cochlea

The cochlea is a snail-shaped structure located within the inner ear. It is crucial for hearing and is where the organ of Corti resides. Within the cochlea, sound waves are converted into neural signals.
Sound vibrations traveling through the ear drum and middle ear bones reach the cochlea as fluid waves.
As these waves travel through the cochlea, they stimulate hair cells to generate the information sent to the brain.

• It is divided into three fluid-filled sections: Scala vestibuli, Scala media, and Scala tympani.
• The structure’s spiral shape allows for a high density of hair cells in a confined space.
• This specific design is essential for distinguishing sound frequencies.

The cochlea is truly a masterpiece of nature’s engineering, translating physical waveforms into auditory experiences.

Inner Ear

The inner ear is a complex structure that plays vital roles in both hearing and balance. Located deep inside the head, it contains the cochlea, vestibule, and semicircular canals.

• The cochlea is responsible for processing auditory information.
• The vestibule and semicircular canals are critical for maintaining balance and body orientation.

Besides its functional importance, the inner ear's fluid-filled spaces provide a unique environment for sound conduction and balance perception.
The airtight and delicate structures ensure sound waves are accurately converted into signals for auditory processing.
Disorders in the inner ear can lead to hearing loss or balance issues, underlining the importance of maintaining ear health. By understanding the inner ear's roles, one can better appreciate its significance in daily life functionality.

Scala Media

Also known as the cochlear duct, the Scala media is one of the three key chambers in the cochlea. It is sandwiched between the Scala vestibuli and Scala tympani, playing a central role in hearing.
The Scala media is where the organ of Corti is situated and is filled with endolymph, a unique fluid crucial for auditory transduction.

• It is bounded by the Reissner's membrane at the top and the basilar membrane at the bottom.
• The hair cells in this duct are connected to nerve fibers that send sound signals to the brain.
• The senior role of the Scala media is to process tones and pitches due to its specific ion-rich environment.

The Scala media’s structure and its contents are critical for distinguishing the wide array of noises we hear daily, demonstrating the incredible intricacy of hearing.