BIOL 4380 Lecture Notes - Lecture 8: Voltage-Dependent Calcium Channel, Vestibular Duct, Tectorial Membrane
13 May 2018
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o The tensor tympani is the muscles of the middle ear: involved in the mediating how
tympanic membrane transduces audio frequencies through oscicles.
o The loatio of the skull so lose to the tpai erae → ou a’t atuall hear
the iratios traellig the oes of the skull ad ot through the air, → possile to
hear vibrations travelling through your skull.
o Cochlea (inner ear), a couple of nerves attached to cochlea: auditory and vestibular
nerves.
▪ Cochlea has 2 important opening:
▪ The oval window (located underneath stapes) and the round window.
▪ The cochlea has 2 separate compartments (both liquid filled): the bottom
compartment is called scala tympani and th etp part is the scala vestibuli, and a
third one called scala media. The apparatus that senses the sound is located in
the middle of the 2 compartments.
▪ There are epithelial cells and a parallel membrane.
▪ Inner hair cells and the outer hair cells. The inner hair cells (the most important
for the perception of sound) are innervated with afferent axons, the outer hair
cells innervated with efferent axons. The 2 membranes are called the basilar
membrane and top one is called the tectorial membrane. No need to know the
tunnel of corti.
▪ The critical sensory components are the stereocilia: in the inner hair cells, there
are hair like strutures alled stereoilia, are V shaped. These are’t true ilia
and are purely actin based.
▪ The ganglion that contains all of these neuronal cell bodies that innervate the
inner and outer hair cells are called the spiral ganglion.
▪ Lots of studies have shown that the structure of the inner ear is what
determines the discrimination between sound frequencies. Low frequency
signals travel quite far down the cochlea whereas very high frequency signals
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The apparatus that senses the sound is located in the middle of the 2 compartments: there are epithelial cells and a parallel membrane. Inner hair cells and the outer hair cells. The inner hair cells (the most important for the perception of sound) are innervated with afferent axons, the outer hair cells innervated with efferent axons. The 2 membranes are called the basilar membrane and top one is called the tectorial membrane. No need to know the tunnel of corti: the critical sensory components are the stereocilia: in the inner hair cells, there are hair like stru(cid:272)tures (cid:272)alled stereo(cid:272)ilia, are v shaped. These are(cid:374)"t true (cid:272)ilia and are purely actin based: the ganglion that contains all of these neuronal cell bodies that innervate the inner and outer hair cells are called the spiral ganglion. Lots of studies have shown that the structure of the inner ear is what determines the discrimination between sound frequencies.
