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

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.