Human Ear: Cochlea (Auditory Organ), the Reissner's Membrane
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Cochlea (Auditory Organ)
The coiled portion of the membranous labyrinth which looks like a snail.
This is made up of three canals:
Upper vestibular canal or scala vestibule.
Middle cochlear duct or scala media.
The lower tympanic canal or scala tympani.
The Reissner’s Membrane
It separates scala media and scala vestibule.
Also known as the vestibular membrane or the vestibular wall.
It creates a compartment in the cochlea filled with endolymph together with the basilar membrane.
Stereocilia
It projects from the hair cells and extend till the cochlear duct.
The tectorial membrane is the other membrane present above hair cells.
The pressure waves are detected using the hair cells present in the cochlea.
Vestibular Apparatus (Equilibrium Organ)
It is present above the cochlea and it helps in maintaining the equilibrium.
It is present in the membranous labyrinth.
Saccule and utricle are the two sacs like chambers along with three circular canals.
Saccule and utricle have macula, a projecting ridge.
Otoliths are calcium ear stones.
Crista ampullaris contain hair cells present in each of the ampulla responsible for sensing angular rotation.
Clinical Significance

Clinical Significance
Vertigo
It refers to the inappropriate perception of motion due to dysfunction of the vestibular system.
Benign paroxysmal positional vertigo is one common type of vertigo.
An otolith is displaced from the ventricles to the semicircular canal.
Result in the perception of vertigo:
Ménière’s disease
labyrinthitis
Strokes
Other infective and congenital diseases
Tinnitus
When there is no external sound, tinnitus is the hearing sound.
It may also sound like a clicking, hiss or roaring though often described as the ringing.
Unclear voices or music are heard rarely.
The sound may be soft or loud, low pitched or high pitched.
The sound causes depression, anxiety, or concentration difficulties in some people.
It is not a disease but a symptom that can be caused by noise-induced hearing loss.
Some other causes are ear infections, disease of the heart or blood vessels, Ménière’s disease, brain tumors, emotional stress, etc.
FAQs
Q 1. Is Tinnitus a disease or just a symptom?
Answer: Tinnitus is not a disease and just a symptom may be caused due to a few reasons such as ear infections, disease of the heart or blood vessels, Ménière’s disease, brain tumors, emotional stress, etc.
Q 2. What is The Reissner’s membrane?
Answer:
The Reissner’s membrane separates scala media and scala vestibule.
Also known as the vestibular membrane or the vestibular wall.
It creates a compartment in the cochlea filled with endolymph together with the basilar membrane.
Q 3. What are the three main classification of Physiology of ear?
Answer:
The three main classification of Physiology of ear are:
The organ of Corti (Cochlea)
Performs the hearing function.
Maculae (Saccule and Utricle)
This is responsible for static equilibrium.
Cristae (semicircular canals)
This is responsible for dynamic equilibrium.
Q 4. What is Cochlea (Auditory Organ?)
Answer:
The coiled portion of the membranous labyrinth which looks like a snail.
This is made up of three canals:
Upper vestibular canal or scala vestibule.
Middle cochlear duct or scala media.
The lower tympanic canal or scala tympani.