Observation of apical part and nerve terminals of human vestibular hair cells.
The human vestibular sensory epithelia of macula utriculi in 3 cases of acoustic neurinoma were examined by conventional and intermediate voltage electron microscopes. The apical part and the nerve terminals of hair cells were studied by means of a computer-aided three-dimensional (3-D) reconstruction technique. The sensory epithelia were fairly well preserved. Most type I and all type II hair cells appeared as those described in the other reports. However, some type I hair cells were incompletely surrounded by nerve calyces and received direct contacts from the efferent nerve endings. These type I hair cells were also innervated by a few neighbouring afferent nerve calyces. The stereocilia and the cuticular plate of type I hair cells differed from those of type II hair cells. The mean diameter of type I hair cell stereocilia was 488 +/- 59 nm and that of type II hair cells was 373 +/- 21 nm. The cuticular plate of type I hair cells resembled a cone and was about several times as thick as that of type II hair cells which was similar to a flat disc.
Morita
I
I
Department of Otolaryngology, Tokyo Medical and Dental University, Japan.
Komatsuzaki
A
A
Kanda
T
T
Tatsuoka
H
H
Chiba
T
T
D002462:Cell Membrane / Q000648:ultrastructure*; D006198:Hair Cells, Auditory / Q000648:ultrastructure*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009411:Nerve Endings / Q000648:ultrastructure*; D009464:Neuroma, Acoustic / Q000473:pathology*; D014722:Vestibule, Labyrinth / Q000473:pathology*