Anatomy of Human Ear

The ear is one of the 5 sense organs of the body and thus it is a sensitive organ of the body. It is used for identification, transaction and conversion of forms of the sound. A further critical job that the human ear does is maintaining balance.

In this article we will be discussing the structure and function of the ear.

Definition:

Ear is one of the sensory organs which makes us able to hear. It does not help in only hearing but simultaneously it helps to maintain the balance of the body as well.

Structure of the Ear

There are 3 parts of the ear:

1. External Ear
2. Middle Ear
3. Inner Ear

All these 3 parts of the ear are explained below

External Ear :

This is the outer part of the year and it is quite visible with the naked eye. It is further divided into three types

i. Auricle(Pinna): The pinna is made up of a thin layer of cartilage which is elastic in nature and covered by the layer of the skin. Its structure is very similar to a funnel which helps to collect the sound and helps to send the sound in the middle ear. The lobule of the pinna is made up of adipose and fibrous tissues with the blood capillaries inside it.

ii. The Ear Canal : It is a canal which is slightly curved in nature and is assisted

by bone anteriorly and by cartilage in its outer part. The ear canal is also called

external auditory meatus. It has a thin layer of stratified epithelium and wax glands.

iii.Ear Drum : It is also known as the tympanic membrane and this membrane

separates between the middle ear and the external ear. The function of this part is to

receiving and amplifying the sound waves.

Middle Ear

It connects the outer or external and internal part of the ear.

i. Tympanic Cavity:

It is the cavity which is situated between the outer and internal part of the ear. It is

separated from the external ear by tympanic membrane and with the help of bony wall

it is separated from the internal ear. It consists the eustachian tube which is known

auditory tube situated internally.

ii.Eustachian Tube

The length of the tube is 4 cm which helps to equalize the pressure on both the sides of

the eustachian tube.

iii.Ossicles

Transmission of the sound waves from the eardrum to the middle year is done by this

part of the ear. It also has three types:

a. Malleus : This ossicle can be considered as the largest, and it is hammered

shape in nature. A handle helps it to connect to the tympanic membrane and

with the help of incus it is attached to the head.

b.Incus : It is an ear ossicle which is anvil shaped in nature and connected to

stapes.

c. Stapes : This ossicle is the smallest and smallest bone in the body as well.

Inner Ear

It is the innermost part of the ear and consisting two types

i. Bony Labyrinth

This part of the ear consists few parts which are: a vestibule, three semi circular

canals and cochlea which are spiral in shape.

ii. Membranous Labyrinth

This part of the year is covered by a bony labyrinth. It is an important part as it has

some receptors which are sensitive and responsible for hearing and simultaneously for

the balance as well.Examples of sensory receptors include the ampullaris macula and

cristae, an organ of the cortex. The three semicircular ducts that make up the

endolymph-filled membrane labyrinths are the cochlear duct, saccule, and utricle

Function of Ear

As much as we have discussed till now, it is quite understood that the ear has mainly two functions which are hearing and balancing.

Hearing

There are few processes those are responsible for the mechanism for hearing or we can say

that there are some processes which make ear to hear and this processes are mentioned

below:

• The sound wave travels through the parts of the outer ear and reaches to the eardrum.
• The reached sound to the eardrum helps the eardrum to vibrate.
• The vibrations which are produced here go through the tympanic membrane and reach up to the tympanic cavity.
• The vibrations are picked up by the ear ossicles further and the stapes force the oval window to move in and out.
• This action further passes to an organ called corti, which acts as a receptor for hearing and it also has small hair cells which convert these vibrations into electrical impulse, and with the help of sensory nerves it passes to the brain.

Balance

There are some parts which are responsible for this function of the ear and those are

• Eustachian Tube and Vestibular Complex

Since the eustachian tube maintains the pressure thus it helps to balance and receptors which maintain the body balance are being kept by the vestibular complex.

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