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 9th, page 347, fig. 19-7 & fig 19-9)
with the cochlear nerve: |
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) Here is a labeled view of the 40x view including the cochlear nerve. |
|
Cochlea, showing helicotrema and an intact set of
membranes:
vestibular membrane |
|
Cochlear duct detail, 100x: (MF 9th,
page
347, fig 19-8.) organ of corti tectorial membrane hair cells (orange at tips) internal spiral sulcus basilar membrane spiral ligament cochlear duct Here is the image labeled . 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) |
|
| Crista Ampullaris, 400x Hair cells can be made out. |
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