Download vestibulocochlear apparatus

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

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Divided into 3 spaces
Scala vestibuli
Scala media
Scala tympani
ORGAN OF CORTI