Problem 107 - Objective Biology for NEET

Question

Ear performs which of the following sensory functions? (A) Vision (B) Olfaction (C) Hearing (D) Maintenance of body balance (a) A, B, C (b) B and C Only (c) C and D Only (d) C Only

Step-by-Step Solution

Answer

The correct answer is (c) C and D Only. The ear performs the sensory functions of hearing and maintenance of body balance.

Step 1: Understanding sensory systems

The first step is to understand what each of the sensory functions listed in the options correspond to in the human body. Vision has to do with the ability to see and hence is connected to the eyes. Olfaction refers to the sense of smell which is a function of the nose. Hearing corresponds to our ability to perceive sound, and is hence connected to the ears. Finally, maintenance of body balance (equilibrioception) has to do with the ability to sense the position of the body relative to gravity, and also involves the ears, specifically the vestibular system.

Step 2: Connecting the functions to the ears

Looking at the functions given and comparing them to the knowledge of the sensory system obtained in Step 1 we can eliminate functions that aren't associated with the ears. This excludes Vision (A), as this is a function of the eyes, and Olfaction (B), as this is a function of the nose. This leaves us with Hearing (C) and Maintenance of Body Balance (D), both of which involve the ears.

Step 3: Formulating the answer

The final step involves connecting the sensory functions attributed to the ear (i.e., Hearing and Maintenance of Body Balance) to the possible answers. Among the given options, the only one that includes both 'C' and 'D' is option (c) C and D Only.

Key Concepts

Hearing

Hearing is one of the primary sensory functions of the ear, enabling us to perceive sound. Sounds are produced by vibrations that travel through the air as sound waves. Our ears are adept at capturing these sound waves and converting them into electrical signals that our brains can understand.

The process of hearing involves several key components:

• The outer ear collects sound waves and funnels them through the ear canal to the eardrum.
• These waves cause the eardrum to vibrate, and these vibrations are transmitted to three tiny bones in the middle ear known as the ossicles.
• The vibrations from the ossicles are transferred to the cochlea in the inner ear. Here, the mechanical vibrations are converted into electrical signals by hair cells.
• The auditory nerve then carries these signals to the brain, where they are interpreted as sound.

Each part of the ear has a specific role, working together to allow us to appreciate a wide range of sounds, from a whisper to thunder.

Body Balance

Body balance, or equilibrioception, is another critical function of the ear. This system allows us to maintain our posture and control our movements, even when our environment changes. The tiny structures in the ear help us sense changes in head position and motion, crucial for body balance.

Here’s how the ear contributes to maintaining body balance:

• The semicircular canals detect rotational movement. These structures are filled with fluid and lined with hair cells that move as the fluid shifts, helping us sense direction and speed of rotation.
• The otolithic organs (utricle and saccule) help sense linear movements, like moving forward or backward, and the position of our head relative to gravity.
• Together, these components send information to the brain, which integrates input from both ears and from the eyes and muscles, helping us stay balanced.

Even slight disruptions to this system can affect balance, causing dizziness or disorientation.

Vestibular System

The vestibular system refers to the structures and functions that assist in body balance and orientation. Located within the inner ear, this system includes the semicircular canals and otolithic organs, as mentioned earlier. These components play a crucial role in helping the brain process information about motion, head position, and spatial orientation.

The vestibular system functions effectively through:

• Semicircular canals that detect head rotations. Each of the three canals corresponds to a different plane of movement.
• Otolithic organs which assess linear accelerations and the effects of gravity.
• Communication with the brain and other sensory organs to help maintain equilibrium and gaze stabilization.

Understanding the vestibular system is essential, as any impairment can lead to conditions such as vertigo, which is characterized by the sensation of spinning or swaying, indicating how crucial this system is for our daily functioning.