Organ of Corti

This prevents the hair cells from touching the endolymph

Reticular lamina

Separates the inner and outer cell structures, filled with cortilymph

Tunnel of Corti

Basilar membrane length

25-35mm

Impedance on BM

Base is narrow and thick

Apex is wide and thin

Base have more mass or stiffness?

Less mass, more stiffness

impedes low frequencies, admits high frequencies 

Apex have more or less stiffness?

More mass, less stiffness

impedes high frequencies

admits low frequencies

Does the tectorial membrane make contact with hair cells?

Makes contact with the tallest stereocilia of OHC, but does not make contact with the IHC

IHC characteristics

Single row

~3500 cells 

Spindle shaped

Cilia not embedded in the tectorial membrane 

OHC characteristics

3-5 rows

~12000 cells

test tube shaped

Stereocilia

top end of the hair cells

Kinocilium

tallest of the stereocilia for each hair cell

IHC stereocilia characteristics

shallow U shape

50-70 cilia per cell arranged in increasing height

IHC cilia are stronger than OHC

OHC stereocilia characteristics

V or W shaped

around 58 to 150 cilia per cell arranged in increasing height

Tip links

tip to side

help strengthen the stereocilia

play an important role in the sensory function of hair cells

First affected hair cells after noise exposure

OHC

Supporting cells

Support the hair cells and the BM

may help maintain the ionic balance in the cochlea

Cells that support IHC

Inner phalangeal cells

Cells that support OHCs

Dieter’s cells

 

1. Bony wall

2. Spiral ligament

3. Stria vascularis

4. Claudius cells

5. Hensen's cells

6. OHC

7. Tunnel of Corti

8. IHC

9. Tectorial Mem.

10. Spiral limbus

11. Reissner's Mem.