High resolution scanning electron microscopy of the human organ of Corti.A study using freshly fixed surgical specimens

Abstract

Scanning electron microscopy on immediately fixed human cochleae obtained during surgery for life-threatening petro-clival meningioma showed excellently preserved morphology. We compared the morphological findings with those from transmission electron microscopic sections of well preserved human and animal tissue. The characteristics of neural innervation, the pathways of the nerves through the organ of Corti and the intimate relation of nerves to supporting cells along their route could be studied in detail. The lateral membranes of Hensen and Claudius cells were folded creating a surface enlargement. Marginal pillars extended the distal end of the tectorial membrane and correspond to the marginal net or "randfasernetz" described earlier. Stereocilia imprints at the undersurface of the tectorial membrane go as far as to the distal end of the marginal pillars. The presence of an irregularly distributed fourth row of outer hair cell, attached to the marginal pillars, raises questions about differences in the excitation of the last row of outer hair cells. The complex nature of many supporting cells, stria vascularis and Reissner's membrane, intracellular complexities as well as surface features are described. Supernumerary inner hair cells were observed and the different arrangement of outer spiral fibres in contrast to findings in animals and variations of nerve fibres within the organ of Corti between apex and base are discussed.

The Human Spiral Ganglion: New Insights into Ultrastructure, Survival Rate and Implications for Cochlear Implants

“…Excellent tissue fi xation is assessed by the absence of cellular protrusions at the reticular lamina [Gleeson, 1985;Glueckert et al, 2005]. This unique material allowed us to identify structural characteristics of this tissue not previously described.…”

“…This adds insights into the surface structure of the modiolar wall and its relation to the spiral ganglion. We previously published results from transmission electron microscopy (TEM) studies of the human spiral ganglion using surgically obtained tissue , 2000aTylstedt et al, 1997;Tylstedt and RaskAndersen, 2001] and on the organ of Corti using SEM [Glueckert et al, 2005]. This represents the fi rst such study to detail the morphology and characteristics of the human spiral ganglion using SEM and sectioned material.…”

Molecular organization and fine structure of the human tectorial membrane: is it replenished?

“…In the middle turn, the marginal band was delicate and displayed a marginal network, which in earlier literature was based on animal work, and named Brandfasernetz^. In human TEM sections, a marginal net with fine struts was attached to the Deiters pillar heads adjacent to Hensen's cells that appeared to keep the TM close to the reticular lamina (Glueckert et al 2005). It is thought to anchor the TM onto the lateral aspect of the acoustic ridge.…”

Estimation of optimal insertion angle in a mammalian outer hair cell stereocilium

“…The geometry of the OHC stereocilia and the TM were constructed in the FE model based on the measurement data reported in the literature (Bohnke et al, 1999;Glueckert et al, 2005;Hemmert et al, 2000;Tsuprun and Santi, 1998;Yoon et al, 2011). Structurally, the TM spans the entire length of the cochlea, which is approximately 100 mm wide and 50 mm thick.…”

“…Properties Values References Stereocilium Length 5 mm ( Glueckert et al, 2005) Diameter 300 nm (Bohnke et al, 1999;Tsuprun and Santi, 1998) Initial insertion length inside the TM 100 nm (Bohnke et al, 1999;Tsuprun and Santi, 1998) TM…”