Neurology of The Ear

The inner ear is divided into 3 sections, outer ear, middle ear and inner ear . The parts of the middle ear amplifies sound waves and transfers them from the air into the fluid in inner ear. The fluid filled inner ear changes the sound waves to nerve signals inside the snail shaped cochlea. The 8th cranial nerve called the Vestibulocochlear nerve and is made up of auditory and vestibular nerves. This carries nerves impulses for both hearing and balance from the ear to the brain (CNS). In diagram: (16) Vestibular Nerve, (21) Internal Auditory canal to the brain.

Sound waves cause the Tympanic membrane (eardrum) to vibrate Sound waves cause the Tympanic membrane (eardrum) to vibrate. Inside the ear there are 3 bones in the middle of the ear, the Malleus, Incus and Stapes, they pass vibrations into the cochlea. The Cochlea is a small shaped fluid filled structure in the inner ear. Special nerve cells pick up the sound waves in the fluid and generate nerve impulses. In the diagram: (1) External Auditory Canal, (2) Tympanic Membrane (eardrum), (3) Malleus, (4) Incus, (5) Stapes, (10)Cochlea, (11) Cochlea Nerve.

The middle ear cavity connects to the throat via the Eustachian tube and so to the air outside. This allows atmospheric pressure to transfer to the cavity, balancing the air pressure on either side of the eardrum and preventing it from bulging as the outside pressure changes. In the Diagram: (7) Eustachian Tube, (21) Internal Auditory Canal to the Brain.

Ear Pathologies There are several different types of disorders which may occur when the nerves in the ear are damaged. Loud noises, infections, head injuries, brain damage and hearing loss are some of a few. Although hearing loss is commonly associated with older people, there are different types of hearing loss.

Different Types Of Hearing Loss Presbycusis - Occurs because of changes in the Inner Ear. Conductive – Occurs when sound vibrations from the Tympanic membrane (eardrum) to the inner ear are blocked, (ear wax) in the auditory canal, also fluid build up in the middle ear, ear infections or abnormal bone growth. Sensorineural – Occur when there is damage to the auditory nerve. For example, like with head injuries, high blood pressure or stroke.

Other Parts of The Ear In Diagram (6) Ligament, (8) Oval Window, (9) Round Window, (12) Semicircular Canals, (13) Utricle, (14) Saccule, (15) Endolymphatic Sac, (17) Facial Nerve, (18) Temporal Bone, (19) Mucle, (20) Cartilage,.