Problem 120 - Objective Biology for NEET

Question

In man the receptors stimulated by sound waves are (a) Organ of corti (b) Semicircular canal (c) Utriculus (d) Sacculus

Step-by-Step Solution

Answer

The receptors stimulated by sound waves in man are located in the (a) Organ of Corti.

Step 1: Understanding the function of various ear components

The semicircular canal, utriculus, and sacculus are all parts of the vestibular system, which is responsible for balance and spatial orientation, not for processing sound waves. On the contrary, the Organ of Corti, located within the cochlea, is the main organ for hearing.

Step 2: Identifying the correct ear component

Given that the question asks for the receptors stimulated by sound waves, it can be concluded that the correct answer must be the part of the ear that is relevant for hearing. In this case, that is the Organ of Corti. The other options are all parts of the vestibular system, which does not process sound.

Step 3: Verifying the correct answer

The Organ of Corti contains hair cells that are stimulated by sound waves, triggering nerve impulses that are sent to the brain and interpreted as sound. Therefore, the correct answer is indeed (a) Organ of Corti.

Key Concepts

Human Ear Anatomy

The human ear is a complex structure vital for both hearing and balance. It consists of three primary parts: the outer ear, middle ear, and inner ear.
The outer ear, visible to others, gathers sound waves from the environment and funnels them through the ear canal to the eardrum.
The middle ear is home to three small bones known as the ossicles, which amplify sound vibrations from the eardrum, directing them to the inner ear.
The inner ear, which includes the cochlea and vestibular system, plays a crucial role in both hearing and balance. The cochlea, shaped like a snail, houses the Organ of Corti. This organ is key for converting sound vibrations into electrical signals through its tiny hair cells.

• Outer Ear: Captures sound.
• Middle Ear: Amplifies sound.
• Inner Ear: Processes sound into signals and maintains balance.

Each part works together harmoniously to enable the complex processes of hearing and maintaining equilibrium.

Hearing Process

The hearing process is a fascinating journey of sound, beginning as vibrations and ending as electrical signals processed by the brain.
It starts when sound waves enter the ear canal, hitting the eardrum, causing it to vibrate. These vibrations are transferred via the ossicles in the middle ear to the cochlea in the inner ear.
Within the cochlea, specifically in the Organ of Corti, thousands of hair cells convert these mechanical vibrations into electrical impulses. These impulses then travel through the auditory nerve to the brain, where they are interpreted as distinct sounds.

• Sound waves create vibrations at the eardrum.
• Bones in the middle ear amplify these vibrations.
• Hair cells in the cochlea transform them into electrical impulses.
• Impulses are sent to the brain for interpretation.

The precision of this process allows us to detect pitch, tone, and volume, ultimately enabling us to enjoy and communicate through diverse sounds.

Vestibular System Aspects

The vestibular system, although located in the inner ear alongside the hearing apparatus, serves a completely different purpose.
Its main role is to help maintain balance and spatial orientation, making sure we can move our heads and bodies without losing equilibrium.
This system comprises the semicircular canals, along with the utriculus and sacculus. These parts contain fluid and sensory hair cells similar to those in the Organ of Corti but are sensitive to changes in head position and motion rather than sound.

• Semicircular Canals: Detect rotational movements.
• Utriculus and Sacculus: Sense linear movements and gravitational forces.

The vestibular system sends signals to the brain about motion and positioning, which helps in coordinating balance with visual and skeletal muscular inputs.
Understanding the vestibular system is essential for grasping how we maintain our balance and navigate through our environment effectively.