Physiology of inner ear

1. Physiology of Inner Ear
Dr. Sara Sadiq
(MBBS, M.Phil)

3. Cochlea
• A spiral shaped fluid filled
structure
• Coiled tube making 2.5 to 2.75
turns around a central pyramid
of bone  Modiolus

20. Physiology of Hearing
• Auricle  external auditory canal
• When sound waves strike eardrum
that cause eardrum to vibrate
• The central area of Ear drum is
connected to malleus which starts to
vibrate. The vibration is transmitted
from malleus to incus then to stapes
• As a stapes moves back and forth it
pushes the membrane of oval
window in and out

21. Physiology of Hearing
• The oval window bulges inward it pushes on perilymph of scala
vestibule
• The pressure waves transmitted from scala vestibuli to scala tempani
that push the vestibular membrane back and forth creating the
pressure waves in the endolymph inside the cochlear duct.
• The pressure waves in endolymph cause basilar membrane to vibrate,
which moves hair cells in the spiral organ against the tectorial
membrane
• Bending of hair cells stereocilia produces receptor potential that lead
to generation of nerve impulses

22. Thank You