Histological Studies of Endolymph Secretion and Resorption in the Inner Ear

Scanning Electron Microscopy of the Endolymphatic Sac Epithelium

“…This was further supported by finding cellular debris on the surface of these cells. The cells occasionally found protruding into the lumen of the intermediate part, also supported the previous concepts of other investigators that some of the free phagocytic cells in endolymph, have been derived from these dark cells Kibata, 1927;Yamakawa, 1929;Siirala, 1942\Saxen, 1951Schindler et al, 1974).…”

Scanning electron microscopy of the connective tissue along the lateral wall of the mouse cochlear duct with special reference to the External sulcus cells.

“…Previous investigators (SAXEN, 1948(SAXEN, ,1951BORGHESAN, 1957;YAMAMOTO and NAKAI, 1964;DUVALL, 1969;KIMURA and OTA, 1974;HAw-KINS, 1976) indicated that the capillaries in the spiral ligament run between the sulcus cell cords and occasionally contact with the sulcus cells, suggesting that the sulcus cell cords absorb endolymph from the cochlear duct and transport it to the capillaries. Thus, the stria vascularis and the external sulcus cells seem to form a system combined with vasculatures for the localized secretion and absorption of endolymph in the cochlear duct.…”

“…Ultrastructural studies have suggested that the sulcus cells secrete (LAWRANCE, 1956;BORGHESAN, 1957;GIEBEL, 1977;GALIC and GIEBEL, 1989) or absorb (SAXEN, 1948(SAXEN, , 1951YAMAMOTO and NAKAI, 1964;SPOENDLIN, 1967b;DUVALL, 1969) endolymph in the cochlear duct. Recent biochemical studies (see the review by STERKERS et al, 1988) have revealed a base-to-apex gradient for the chemical composition of the endolymph, implying that the cochlear components involved in the secretion and absorption of endolymph vary in functional structure along the cochlear duct, but the sulcus cell cords have never been studied in this respect.…”

“…The spiral ligament with the insertion of the branching sulcus cell cords is rich in capillary networks draining the blood from the capillary networks in the stria vascularis (SMITH, 1954(SMITH, , 1957, which is generally believed to secrete endolymph in the cochlear duct (SAXEN, 1951;SMITH, 1957;BORGHESAN, 1957;SPOENDLIN, 1967a). Previous investigators (SAXEN, 1948(SAXEN, ,1951BORGHESAN, 1957;YAMAMOTO and NAKAI, 1964;DUVALL, 1969;KIMURA and OTA, 1974;HAw-KINS, 1976) indicated that the capillaries in the spiral ligament run between the sulcus cell cords and occasionally contact with the sulcus cells, suggesting that the sulcus cell cords absorb endolymph from the cochlear duct and transport it to the capillaries.…”