Problem 129 - Objective Biology for NEET

Question

Malleus (hammer shape), incus (anvil shape) and stapes (stirrup shape) are present in (a) Internal ear of frog (b) Middle ear of human (c) Eye of rabbit (d) Eye of frog

Step-by-Step Solution

Answer

The malleus, incus, and stapes are present in the option (b) Middle ear of a human.

Step 1: Knowledge of ear anatomy

Understand that the malleus, incus, and stapes are bones found in the ear of certain mammals. Known collectively as the ossicles, these bones are involved in the process of converting sound waves into vibrations that the inner ear can translate into neural signals.

Step 2: Identify the species with these structures

Compare the options given in the exercise. The malleus, incus, and stapes are specifically present in the ear of mammals.

Step 3: Confirm the correct answer

The species among the options that is known to possess these structures is the human. The structures are present specifically in the middle ear, thus the correct answer is option (b) Middle ear of human.

Key Concepts

Ossicles

The ossicles are a crucial part of the human ear anatomy. They are found in most mammals and are known for their role in sound transmission. These tiny bones amplify sound vibrations from the eardrum to the inner ear.
The term "ossicles" refers to three small bones:

• Malleus
• Incus
• Stapes

Together, these bones form a chain called the auditory ossicular chain, which is vital for efficient hearing. When sound waves strike the eardrum, they cause it to vibrate. These vibrations are then transferred to the ossicles, which amplify and guide them towards the inner ear. Due to their unique arrangement and function, they enhance our ability to hear a wide range of frequencies.

Malleus Incus Stapes

The bones known as the malleus, incus, and stapes are the smallest bones in the human body. Each bone has a unique shape and function:

• Malleus - Also known as the "hammer," the malleus connects to the eardrum and starts the chain reaction by transferring vibrations to the incus.
• Incus - Known as the "anvil," the incus takes the vibrations from the malleus and passes them to the stapes.
• Stapes - Referred to as the "stirrup," the stapes fits into the oval window of the cochlea, helping to convey the vibrations into the inner ear fluid.

These bones work as a team to transmit sound efficiently from the outer ear to the inner ear.
Their connection and movement are essential to translating sound vibrations into signals that the brain interprets as hearing.

Middle Ear

The middle ear is a vital component of human ear anatomy that houses the ossicles. It is located between the outer ear and the inner ear and serves as a sound transmission chamber.
The main elements of the middle ear include:

• The Tympanic Membrane (Eardrum) - It marks the boundary between the outer ear and middle ear and vibrates when sound waves hit.
• The Ossicles - The bones within the middle ear that transmit sound from the eardrum to the inner ear.
• The Eustachian Tube - It connects the middle ear to the throat and helps equalize pressure, ensuring the eardrum can vibrate correctly.

The air-filled space of the middle ear allows the ossicles to move freely, which is crucial for sound transmission.
The middle ear acts as an amplifier, magnifying sound waves before they reach the inner ear for further processing.