Ear

Cochlear Nerve

Collects sensory information from the cochlea (specifically the Organ of Corti) and sends it to the brain.

Vestibular Nerve

Collects sensory information from the semicircular canals (and the utricle and saccule) and sends it to the brain.

cochlea

The chamber of the cochlea is bony and conical and it tapers off into a coiled structure. The Organ of Corti is the sensory component inside the cochlea and it is located within the coiled portion. As the fluid (perilymph) with the cochlea moves (due to the mechanical disturbance of the stapes on the oval window), the cilia on the hair cells found on the Organ of Corti are displaced. This motion is converted into electrical impulses that get sent to the cochlear nerve which sends the signals to the brain.

Oval Window

The oval window is a flexible membrane covered opening at the upper part of the cochlea called the vestibule. The stapes of the middle ear vibrates against the oval window which transmits the vibrations within the fluid contained in the cochlea.

Tympanic Cavity

The space within which the ossicles are located. It connects to the Eustachian tube, but is separated from the auditory canal by the tympanic membrane.

Semicircular Canals

These three interconnected fluid filled canals in the inner ear contain sensory receptors that send information to the brain that helps you maintain your balance.

Malleus

This first small bone (ossicle) of the middle ear transmits the vibrations from the tympanic membrane to the second bone, the incus.

Tympanic Membrane

This is a cone-shaped membrane that converts sound waves into vibrations which it passes along to the ossicles of the inner ear. This process also results in amplifying the sound wave signals over twenty times before the signal reaches the oval window of the cochlea

Pinna

This is the outer flap of the ear. It is shaped by rigid but flexible cartilage covered in skin. Its shape helps funnel sound waves towards the auditory canal.

Auditory Canal

This is the pathway that directs sound waves to the middle ear (the eardrum specifically). The outer third contain hairs that prevent particles and small insects from entering. It also produces earwax (cerumen) which helps protect, clean and lubricate the canal. It can also provide some minimal protection against infection and water entry.

Round Window

This membrane covered opening located below the oval window allows the fluid in the cochlea to be displaced when the oval window is pushed inwards by the stapes. When this happens, the fluid within the cochlea cannot push against the rigid bony walls of the cochlea, so the incompressible fluid can only be moved if there's a flexible area on the cochlear wall. This area is the round window which bulges out with fluid every time the oval window is depressed by the stapes. This allows the movement of fluid within the cochlea which is needed to move the hair cells on the Organ of Corti.

Incus

This second small bone (ossicle) of the middle ear transmits the vibrations from the malleus to the third bone, the stapes.

Stapes

This third and smallest bone (ossicle) of the middle ear transmits the vibrations from the incus to the oval window of the cochlea to which it is attached. This bone is also the smallest bone in the human body. When it taps against the oval window, this displaces the fluid found within the cochlea.

Eustachian Tube

This tube connects the middle ear (tympanic cavity) to the nasopharynx. This helps drain mucus from the middle ear. It can also be used to help equalize the pressure of the inner ear when external air pressure changes.