Transduction / Structure & Function
Structure/Function Relationships
there are two types of hair cells:
- TYPE I: "true" receptors
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TYPE II: amplifiers
- in the cochlea, type I cells are called INNER HAIR CELLS; type II cells are called OUTER HAIR CELLS (based on their relative position within the organ of Corti)
- there are 3 aspects of hair cell structure that are critical to their function:
- Both types of hair cells are mechanoreceptors.
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stairlike arrangement of stereocilia; longest near the kinocilium
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- Both types of hair cells are mechanoreceptors.
- Type I and type II hair cells have different afferent and efferent innervation.
TYPE I |
TYPE II |
90% of afferents |
10% of afferents |
1 HC/afferent |
many HC/afferent |
efferents terminate on afferent terminals under IHCs |
efferents have large, direct contact with OHC soma |
- In the cochlea, OHCs have specialized lateral cisternae and other structural adaptations that support their function as contractile units