STRUCTURE OF HUMAN EAR

Published on: March 21, 2024

Structure of the Human Ear

The ear is one of the sense organs in the human body. It helps us to hear. Let us see how:

The ear is divided into three parts:

  • Outer ear

  • Middle ear

  • Inner ear


 

Major parts of the ear

Sub-parts

Features


 

Outer ear

Pinna

Collects sound signals from surroundings and sends them to the auditory canal.

Auditory canal

It is a long tube that contains hairs and glands that produce ear wax, which prevents foreign particles from entering the ear.

It sends the sound to the eardrum.

Eardrum

It is also called the tympanic membrane.

It is a thin membrane that vibrates with the sound.

It transmits the sound to the middle ear.



 

Middle ear

Three middle ear bones

Malleus: It is attached to the eardrum. It is hammer-shaped.

Incus: it is attached to the malleus. It is anvil-shaped.

Stapes: It is the smallest bone in the human body. It is stirrup-shaped.

Eustachian tube

It is a canal that connects the middle ear to the inner ear.


 

 

Inner ear

Semicircular canals

These are fluid-filled tubes that help with balancing.

Cochlea

It is spirally coiled.

It converts the sound signals to electrical signals.

It is connected to the brain by auditory nerves.

Auditory nerve

It transmits the electrical signals to the brain. Using this signal, the brain interprets the sound.

Pinna collects the sound from outside. This sound reaches the eardrum through the auditory canal. The eardrum vibrates when there is a pressure difference between the inside and outside of the membrane. The vibrations were amplified by the three bones in the middle ear: the malleus, incus, and stapes. The amplified pressure variations are transmitted through the middle ear to the inner ear. The cochlea converts these into electric signals that are sent into the brain through the auditory nerve. Using the electrical signals, the brain interprets the sound.

 

SUMMARY

  • Sound is produced from the vibration of different objects.

  • Sound travels as a longitudinal wave through a material medium.

  • Sound travels as successive compressions and rarefactions in the medium.

  • In sound propagation, it is the energy of the sound that travels, not the particles of the medium.

  • Sound cannot travel in a vacuum.

  • The change in density from one maximum value to the minimum value and again to the maximum value makes one complete oscillation.

  • The distance between two consecutive compressions or two consecutive rarefactions is called the wavelength, λ.

  • The time taken by the wave for one complete oscillation of the density or pressure of the medium is called the period.

  • The number of complete oscillations per unit of time is called the frequency (ν); 1 ν = T.

  • The speed v, frequency ν, and wavelength λ of sound are related by the equation v = λν.

  • The speed of sound depends primarily on the nature and temperature of the transmitting medium.

  • The law of reflection of sound states that the directions in which the sound is incident and reflected make equal angles with the normal to the reflecting surface at the point of incidence, and the three lie in the same plane.

  • For hearing a distinct sound, the time interval between the original sound and the reflected one must be at least 0.1 s.

  • The persistence of sound in an auditorium is the result of repeated reflections of sound and is called reverberation.

  • Sound properties such as pitch, loudness, and quality are determined by the corresponding wave properties.

  • Loudness is a physiological response of the ear to the intensity of sound.

  • The amount of sound energy passing each second through a unit area is called the intensity of sound.

  • The audible range of hearing for average human beings is in the frequency range of 20 Hz–20 kHz.

  • Sound waves with frequencies below the audible range are termed "infrasonic,” and those above the audible range are termed "ultrasonic.”

  • Ultrasound has many medical and industrial applications.

  • The SONAR technique is used to determine the depth of the sea and to locate underwater hills, valleys, submarines, icebergs, sunken ships, etc.


 

Frequently Asked Questions

Q1. What are the main components of the human ear?

Ans: The human ear comprises three main parts: the outer ear, the middle ear, and the inner ear.

Q2. How does the inner ear contribute to hearing?

Ans: The inner ear contains the cochlea, responsible for converting sound vibrations into electrical signals interpreted by the brain through the auditory nerve.

Q3. What is the purpose of the eardrum?

Ans: The eardrum, located in the middle ear, vibrates in response to sound waves and transmits these vibrations to the ossicles for further processing.

Q4. How does the human ear protect itself from loud sounds?

Ans: The muscles in the middle ear can contract to reduce the transmission of sound, acting as a protective mechanism against excessively loud noises.