VESTIBULOCOCHLEAR APPARATUS Dr Iram Tassaduq INTRODUCTION Ear is

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 components Bony 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