Structure of the Vestibular Sensory Epithelia
The vestibular sensory epithelia are situated on the macula sacculi, the macula utriculi and the three cristac ampullares. Already the early authors (Scarpa, 1789; Steifensand, 1835) were able to follow the nerve fibres to these regions, but Schultze (1858) was the first to give a description of the structure of the sensory epithelium. He described in elasmobr.tinchs three different types of cells, and also observed sensory hairs projecting from the surface of the epithelium. Odenins (1867) made similar findings in man. In the sane year, however, Hasse showed in birds (Hasse, 1867a), and in dogs and cats (liasse. 1967 b) that the sensory epithelium on the cristae and the macula utriculi contained only two different cell types, which, according to his description. correspond to the now recognized sensory cells (hair cells) and supporting cells. The nerve fibres made contact with the sensory cells, and it was also from these cells that the hairs projected. Retzius (1871) found that each sensory hair was not homogenous, but consisted of a number of very fine threads of different lengths. By analogy with previous findings in the organ of Corti, Pritchard (1876) described an increased density of the uppermost structures of the sensory epithelium, and he called this the reticular membrane. After systematic studies (Reteins (1881a, 1884) found that the basic features of the structure of the vestibular sensory epithelia were uniform in all vertebrates. Van der Stricht. (1908) and Held (1909) later showed that the sensory hairs were not all of the same type, as previously believed. but could be differentiated into true sensory hairs and a flagellum.
KeywordsFree Surface Supporting Cell Peripheral Region Sensory Cell Surface Preparation
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