Working of Human Ear

Introduction

Study the different parts of the human ear; it is divided into the external ear or outer ear, the middle ear, and the inner ear. The external and middle ear is concerned with transmitting the sound, while the inner ear has the organ of hearing as well as the organ of balance.

Outer Ear: The outer ear is referred to as the ear canal and the pinna or auricle. Pinna or auricle is the part of the ear that is visible externally. The ear canal has hair and wax-secreting glands. The outer ear protects and channels the sound waves to be transmitted to the middle ear.

Tympanic Membrane- Tympanic membrane is a thin membrane also known as the eardrum that separates the outer ear from the middle ear.

Middle Ear: The middle ear consists of ossicles, which are small bones that are connected to each other and transmit sound waves to the inner ear. There are three ossicles named malleus, incus, and stapes.

Eustachian Tube- The eustachian tube is a canal that connects the middle ear to the back of the nose and the throat. The eustachian tube equalizes the pressure inside the ear with the outside world. This equalized pressure is needed for the proper transfer of sound waves.

Inner Ear- The inner ear has the following structures:

• Cochlea- This contains nerves for hearing.

• Vestibule- This has receptors for balance.

• Semicircular Canals-Has the receptors for balance.

How Does the Human Ear Work?

1. Sound waves pass through the narrow ear canal.

2. This ear canal leads to the eardrum. The sound waves will cause vibration in the eardrum.

3. These vibrations are then transferred to the ossicles, that is, the three tiny bones that are connected to each other in the middle ear.

4. These bones in the middle ear amplify or increase the vibrations. These vibrations then travel to the cochlea, a snail-shaped fluid-filled structure in the inner ear.

5. This cochlea is divided into upper and lower parts by an elastic partition called the basilar membrane.

6. These vibrations will cause disturbance in the fluid inside the cochlea. There are hair cells (receptors of sound) that are located on the basilar membrane. These disturbances in the fluid will lead to the formation of waveforms. These hair cells will sense these waves formed. The hair cells present at the wide part of the cochlea will detect high-pitched sounds, and hair cells closer to the center detect low-pitched sounds.

7. When these hair cells move along the waves, they bump against the overlying structure, causing them to bend. This bending of these cells will lead to the opening of pore channels present on them and chemicals entering the cells, creating an electrical signal.

8. Now, these electrical signals are carried to the brain by the auditory nerves, which are turned into a sound and interpreted by the brain.

What Are the Different Ear Conditions Seen?

• Earache- It is one of the common symptoms in association with most ear conditions. Some of the causes might be serious, and some might not.

• Middle Ear Infection (Otitis Media)- This is the infection of the middle ear caused by a bacterial or viral infection. This condition mainly affects children more than adults.

• Swimmer’s Ear - This is also known as Otitis externa. This is the infection of the outer or external ear, that is, the pinna and the ear canal. This is common in kids who spend too much time in the water.

• Meniere's Disease- This is a chronic disorder that can cause hearing and balance problems. Vertigo, hearing loss, tinnitus, and earache are common symptoms.

• Earwax Impaction- This is also known as cerumen impaction. The ear wax function is to protect the ear canal from water, infection, and foreign bodies, but too much wax build-up could affect the hearing.

• Ruptured Eardrum- A small tear or hole in the eardrum is called the ruptured eardrum. This could affect hearing and can make the middle ear more prone to infections.

• Tinnitus- This is the constant ringing sound heard in the ear. It is not from any external source. This is usually due to exposure to loud noise, hearing loss, or medications.

• Acoustic Neuroma- It is a rare non-cancerous tumor that grows on the auditory and vestibular nerve that travels from the ear to the brain.

• Benign Paroxysmal Positional Vertigo (BPPV)- BPPV is a condition that affects the inner ear and is the most common cause of vertigo (sudden sensation of spinning inside the head).

• Cholesteatoma- It is a non-cancerous growth in the middle ear region behind the ear. There will be foul-smelling discharge associated with hearing loss in this condition.

What Are the Common Ear Tests Done?

• Ear Examination- The first step in diagnosing any ear disease is by doing a physical examination of the ear canal using an otoscope. An otoscope enables one to look into the ear canal till the eardrum.

• Audiometry Exam- This test is done to check how well one can hear.

• CT (Computed Tomography) Scan- A CT scan allows one to visualize the internal structure of the ear in different slices from the ear to the skull bone.

• MRI (Magnetic Resonance Imaging)- A strong magnetic field and very high-frequency radio waves are used to produce highly detailed images of the structures of the ear. These are used to diagnose any growth or fluid collection inside the ear.

How Is Any Ear Condition Treated?

• Antibiotics- As in any bacterial infections, in-ear infections caused by bacteria, the treatment preferred will be antibiotics. The choice, dose, and duration of the antibiotics will be different in different infections. The antibiotics could be given in the form of pills or ear drops.

• Pain Killers- As earache is associated with most of the diseases affecting the ear, pain killers will be advised. Painkillers will help in decreasing this symptom. It is just a symptomatic treatment as it does not resolve the root cause of the disease.

• Earwax Drop- These drops are used to soften, loosen and remove the impacted wax from the ear.

• Lavage- Irrigation of the ear canal with salt water and hydrogen peroxide will help in the treatment of cerumen impaction.

• Antihistamine- The side effect of this Antihistamine is a calming effect on the inner ear and reducing symptoms of vertigo. Hence this disadvantage of these drugs is made use of in the ear disease.

• Surgery- Surgery might be needed in case of any growths inside the ear, like an acoustic neuroma. Also, surgeries are done in children with frequent infections to place a draining tube.

Conclusion

The ear is a complex organ that plays different key roles in the normal functioning of a human. The ear can help you hear as well as to maintain the balance of the body. Any condition which affects this organ can affect the hearing or the balance or both, which is essential for maintaining a normal life. If you feel that you are affected by symptoms related to hearing or balance, do not hesitate to consult a doctor right away.