	HISTOLOGY OF THE INNER EAR ©David B. Fankhauser, Ph.D., Professor of Biology and Chemistry University of Cincinnati Clermont College, Batavia OH 45103
malleus, incus and stapes	This page has been accessed times since 11 February 2003. 18 February 1992, 3 Jan '96, 31 Dec '96, 7 Jan '98, 5 Jan 00, 4 Jan 01	cross section through cochlear loop

Follow protocol Notebook Illustrations

Above left are the three ossicles photographed with a dime to show their relative size. The left most bone is the malleus (hammer) which is attached directly to the typmanic membrane. It transmits vibrations to the incus (anvil) which in turn transmits vibrations to the right most bone, the stapes (stirrup). The flat end of the stapes fits into the oval window of the cochlea which then transmits vibrations into the cochlea along the scala vestibuli.

Examine the following two slides, note the features in common and the differentiating features. Illustrate each at the noted power to take up a page. Compare with the illustrations in di Fiore's Atlas of Normal Human Histology, 9th Ed.

Slide 9: Ear, cochlea., guinea pig, (71571) Two views, and overview, and a detail:
(see MF 9^th, page 347, fig. 19-7 & fig 19-9)

	Cochlea cross section, Overview at 40x: helicotrema scala vestibuli (from oval window) vestibular membrane scala tympani (to round window) basilar membrane cochlear duct organ of corti osseus labyrinth (bony case) spiral lamina (bony core) spiral ganglion cochlear nerve (visible in some)
	Cochlea, showing helicotrema and an intact set of membranes: vestibular membrane basilar membrane
	Cochlear duct detail, 100x: (MF 9^th, page 347, fig 19-8.) organ of corti tectorial membrane hair cells (orange at tips) internal spiral sulcus basilar membrane spiral ligament cochlear duct endolymph vestibular membrane scala vestibuli scala tympani perilymph osseus spiral lamina spiral ganglion
	Organ of Corti organ of corti tectorial membrane hair cells (orange at tips) internal spiral sulcus basilar membrane spiral ligament cochlear duct endolymph vestibular membrane osseus spiral lamina

Slide 11. Crista ampullaris (H 1697)

The semicircular canals detect angular or rotational acceleration. This is a cross section through an ampulla of a semicircular duct. (There is no illustration in di Fiore.)

Semicircular Canal, 40x, cross section
Note boney labyrinth surrounding the canal

Crista Ampullaris, 100x:
crista ampullaris (ridge-like structure)
receptor epithelium (hair cells on crista)
cupola (gelatinous mass on top of the crista)
ampulla of semicircular duct
endolymph (fills the chamber)
membranous labyrinth

Crista Ampullaris, 400x
Hair cells can be made out.

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	Semicircular Canal, 40x, cross section Note boney labyrinth surrounding the canal
	Crista Ampullaris, 100x: crista ampullaris (ridge-like structure) receptor epithelium (hair cells on crista) cupola (gelatinous mass on top of the crista) ampulla of semicircular duct endolymph (fills the chamber) membranous labyrinth
	Crista Ampullaris, 400x Hair cells can be made out.

HISTOLOGY OF

THE INNER EAR