The inner ear, or the labyrinth of the ear, is the part of the ear that has the senses of hearing and equilibrium organs. It is located at the end of the ear tubes and is the deepest part of the ear. The inner ear is also known as auris interna. The main function of the inner ear is to transform sound waves into electrical signals or nerve impulses. This facilitates the hearing and understanding of different sounds by the brain.
The labyrinth inner ear is a bony structure and is like a cavity in the temporal bone. It is divided into three sections:
The cochlea is the auditory part of the internal ear and converts the sound waves into nerve signals. It resembles a small spiral-shaped shell.
They sense the posture and the balance. They help in maintaining the equilibrium.
It lies between the cochlea and the semicircular canals. The vestibule also assists in maintaining equilibrium.
The inner ear structure includes a membranous labyrinth, which is divided into three parts: the semicircular ducts, two saclike structures called the saccule and utricle that are located in the vestibule, and the cochlear duct which plays an important role in hearing.
The cochlear duct creates a shelf-like structure across the cochlea and divides it into two sections: scala tympani and scala vestibuli. The ear fluid name for the cushion-like liquid that covers the inner ear when it lies within the membranous labyrinth is endolymph. When it separates the bony and membranous labyrinths in the inner ear anatomy, this fluid covering the inner ear like a cushion is called the perilymph.
The main functions of the inner ear are to help in hearing and maintain balance or equilibrium. All the parts of internal ear are connected with each other but each of them has a separate role to play. The cochlea coordinates with the outer ear and the middle ear to help in hearing sounds. It is filled with liquid and contains a small structure called the organ of Corti which is very sensitive. It works as the microphone of the body and 4 rows of tiny hairs in it help in picking up the vibrations from the sound waves.
The hearing process or the path of sound involves several steps that occur from the outer ear to all the parts of internal ear. When all the steps are completed, it helps a person hear a sound:
The outer ear visible to the eye plays the role of a funnel and sends sounds from outside into the ear canal.
These sound waves then travel down the ear canal to the eardrum located in the middle ear.
The sound waves create vibrations in the eardrum and move the 3 tiny bones in the middle ear.
This movement in the middle ear leads to pressure waves, making the fluid inside the cochlea move.
The fluid movement in the inner ear bends the tiny hairs in the cochlea and moves them.
The moving or “dancing” hairs in the cochlea change the movement into electrical signals from sound waves.
When electrical signals are sent to the brain via the hearing (auditory) nerves, it makes a sound.
The vestibule and the semicircular canals in the labyrinth ear are responsible for the balance. There are 3 semicircular canals and loop-shaped tubes in the inner ear. They are filled with liquid and are lined with fine hairs, just like in the cochlea. The difference here is that these hairs pick up body movements unlike the hairs in the cochlea that pick up sounds. These hairs play the role of sensors and help in balance.
The semicircular canals in the labyrinth ear are placed at right angles to each other. Their position in the inner ear helps them measure motions at any position that the person is in. When the head moves around, the fluid inside the semicircular canals shift around too and moves the tiny hairs inside them along with it.
The “sacks” in the vestibule have more fluid and hairs in them and they connect the semicircular canals. These sacks are called the saccule and utricle and their function is to sense movement. When these balance and movement sensors send electrical nerve messages to the brain, it sends a command to the body about how to stay balanced.
Two major inner ear conditions include hearing loss and balance problems.
Hearing loss is caused by inner ear conditions called sensorineural. In this case the hairs or nerve cells in the cochlea that help hear a sound get affected. These nerves and hair cells also get damaged due to aging or from experiencing too much loud noise for too long. Hearing loss can also occur when the internal ear is not able to send nerve signals to the brain efficiently.
This problem is caused by labyrinth ear conditions and a person may feel dizziness, vertigo (a room spinning sensation), lightheadedness, or gets unsteady on the feet. These problems can also occur when a person is sitting or lying down.
Q1. Why Does a Person on a Boat or a Rollercoaster that’s Moving Up and Down, Feel Dizziness?
Ans. When a person is on a boat or a rollercoaster that’s moving up and down, they feel dizziness because the fluid in the inner ears takes some time before it stops moving. This causes dizziness for a little while even after the person has stopped moving and is on solid ground.
Q2. What are the Symptoms of a Hearing Loss?
Ans. The symptoms of hearing loss include:
unclear higher pitch tones
difficulty in understanding words
problem in hearing speech against other background noises
difficulty in hearing consonant sounds
difficulty pinpointing where a sound is coming from
Q3. How Can You Keep the Inner Ear Healthy?
Ans. Some ways of keeping the inner ear healthy include
Seeing a doctor in case there is an excess ear wax build-up
Avoid listening to loud music
Using ear protection in airplanes