Structure of Ear

The human ear is a vital organ with one main function: it helps hear sounds. The inner ear (vestibular apparatus) also helps maintain body balance. The ear detects sound waves and sends signals to the brain. It also senses head movement to help maintain balance.

The ear has three main parts:

External ear
Middle ear
Inner ear

Each part plays a different role in hearing and balance.

External Ear

The external ear is the part visible on the outside. It gathers sounds and sends them inside.

Auricle (Pinna)

The auricle is made of flexible cartilage covered with skin. It has curves that help gather sound waves. These waves are sent into the ear canal. The soft lower part has fatty and fibrous tissue and is called a lobule.

External Auditory Meatus

This is a tube-like canal that leads to the eardrum. The outer part has cartilage; the inner part is surrounded by bone. The canal is lined with wax glands and hairs. These help keep dust and insects out.

Tympanic Membrane (Eardrum)

The eardrum is a thin membrane located at the canal’s end. It vibrates when hit by sound waves. These vibrations pass to the bones in the middle ear.

Middle Ear

The middle ear is an air-filled space behind the eardrum. It carries sound vibrations to the inner ear.

Tympanic Cavity

This is a small chamber inside the skull. It is separated from the outer ear by the eardrum. The cavity connects to the back of the nose by a narrow tube.

Eustachian Tube

The Eustachian tube joins the middle ear to the throat and balances air pressure on both sides of the eardrum.

Ear Ossicles

There are three tiny bones in the middle ear.

Malleus looks like a hammer. It attaches to the tympanic membrane and connects with the incus.
Incus looks like an anvil. It connects the malleus and stapes.
Stapes looks like a stirrup. It connects to the inner ear.

It is the tiniest bone in the human body. These bones pass sound vibrations from the eardrum to the inner ear.

Inner Ear

The inner ear is a complex structure deep inside the skull. It helps hear sounds and maintain balance.

Bony Labyrinth

This is the outer part of the inner ear. It includes the cochlea, vestibule, and semicircular canals. It is filled with a fluid called perilymph.

Membranous Labyrinth

This lies inside the bony labyrinth. It is filled with a different fluid, called endolymph. It contains the actual sensory organs for hearing and balance.

The cochlear duct has the organ of Corti, which detects sound.
The utricle and saccule detect linear acceleration and head position
The semicircular ducts sense rotational movement.

Functions of the Ear

The ear helps hear and stay balanced.

Hearing

Sound enters the ear canal, hitting the eardrum. Vibrations then pass through the ear bones to the cochlea. Inside, fluid moves and stimulates hair cells. Hair cells send signals to the brain via the auditory nerve.

Balance

The semicircular canals sense body movement. Other inner ear structures assist in balance. Together, they keep the body stable. The Eustachian tube equalises air pressure across the eardrum but does not directly maintain balance.

Summary

The ear consists of three parts: external, middle, and inner. It helps hear sounds and keep balance. Sound waves create vibrations, which move through the ear bones to the inner ear. There, vibrations turn into signals sent to the brain. The inner ear also senses movement to maintain body stability.

Frequently Asked Questions (FAQs)

Q1. What is the function of the external ear?

A. The external ear collects sound waves. Then directs the sound into the ear canal. This helps begin the hearing process.

Q2. What is the tympanic cavity?

A. The tympanic cavity is an air-filled space. It has tiny bones that pass sound to the inner ear.

Q3. What is the bony labyrinth?

A. The bony labyrinth is the hard outer structure of the inner ear. It encloses the membranous labyrinth, which has the organs for hearing and balance.