Inner and outer hair cells differ structurally and likely function differently

Evidence

As can be seen in Fig. 3.4, the construction of inner and outer haircells is different. The outer haircells are thinner, pillar-shaped and (unlike the inner haircells) not tightly surrounded by supporting cells. There are obvious and regularly occurring differences in the ultrastructure of the two types of haircells. In addition, the afferent synapses of the inner haircells (going towards the brain) appear to possess the normal characteristic of chemical synapses whereas those of the outer haircells are atypical. The structural differences indicate different functions for the inner and outer haircells. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 204

The outer haircells are thinner, pillar-shaped and (unlike the inner haircells) not tightly surrounded by supporting cells. There are obvious and regularly occurring differences in the ultrastructure of the two types of haircells. In addition, the afferent synapses of the inner haircells (going towards the brain) appear to possess the normal characteristic of chemical synapses whereas those of the outer haircells are atypical. The structural differences indicate different functions for the inner and outer haircells. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 204

Categorization

• DEFINE: Clarifies the structural distinction between inner and outer hair cells, foundational anatomy for psychoacoustics.
• QUESTION: What exactly makes outer haircell afferent synapses ‘atypical’? Worth chasing for the mechanistic detail.
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 204