VESTIBULOCOCHLEAR APPARATUS
Dr Iram Tassaduq
INTRODUCTION Ear is related to equilibrium and hearing Consist of 3 parts external ear for sound wave
reception middle ear for transmission of
bones from air to bone inner ear for transduction of
vibrations to nerve impulses
EXTERNAL EAR Pinna having elastic
cartilage External auditory
meatus having coiled tubular glands
Tympanic membrane covered externally by epidermis and internally
by simple cuboidal epithelium
MIDDLE EAR Lined by simple
squamous epithelium
Thin lamina propria Transformation of
simple squamous to pseudostratified ciliated columnar epithelium near auditory tube
INTERNAL EAR Has two
componentsBony labyrinth consist
of cochlea,vestibule and semicircular canals
Membranous labyrinth consist of saccule and utricle filled with endolymph
MEMBRANOUS LABYRINTH
Composed of thin sheet of connective tissue lined with simple squamous epithelium
Have maculae ( regions of differentiated neuroepithelial cells)
STRUCTURE OF MACULA 2 types of receptor
(hair cells)
Supporting cells are columnar in shape with microvilli
Otolith a gelatinous glycoprotien covering this neuro epithelium
ENDOLYMPHATIC DUCT AND SAC
Endolymphatic duct is lined by simple squamous epithelium initially
Simple columnar epithelium near sac
COCHLEAR DUCT Divided into 3
spaces• Scala vestibuli• Scala media• Scala tympani
ORGAN OF CORTI