1' Nucleus 2' Stereocilia 3' Cuticular plate 4' Radial afferent ending dendrite of type I neuron 5'

1
Inner Hair Cells
1. Nucleus2. Stereocilia3. Cuticular plate4.
Radial afferent ending (dendrite of type I
neuron)5. Lateral efferent ending6. Medial
efferent ending7. Spiral afferent ending
(dendrite of type II neuron)
2
Outer Hair Cells
1. Nucleus2. Stereocilia3. Cuticular plate4.
Radial afferent ending (dendrite of type I
neuron)5. Lateral efferent ending6. Medial
efferent ending7. Spiral afferent ending
(dendrite of type II neuron)
3

• In the human cochlea, there are
• - 3,500 IHCs and
• - 12,000 OHCs.
• This number is ridiculously low, when compared to
  the millions of photo-receptors in the retina or
  chemo-receptors in the nose!
• In addition, hair cells share with neurons an
  inability to proliferate they are differentiated
• This means that the final number of hair cells is
  reached very early in development (around 10
  weeks of fetal gestation) from this stage on our
  cochlea can only lose hair cells.

4
Scala Vestibuli
Scala Media
Scala Tympani