title: Ciliated receptors in the cruciform muscle sense organ of Scrobicularia plana (Da Costa) (Mollusca Lamellibranchia Tellinacea).
abstract: The ultrastructure of the cruciform muscle sense organ has been studied in Scrobicularia plana. Subepithelial neurons give rise to two different types of ciliated dendrite which pass through a thick basement membrane to insert between epithelial cells lining the sensory pit. Type I, comprising most dendrites have an elongated surface bearing up to 4 rows of 20 cilia, the basal bodies of which are linked in each row. These dendrites, it is suggested, receive unidirectional stimuli. Type II dendrites bear only one cilium surrounded by 9 peculiar microvilli embedded in a conspicuous glycocalyx. The efficient stimulus for this receptor is not known. The two different types possess cilia with (9 X 2) + 2 microtubuli, striated rootlets but no basal foot, surrounded by microvilli.
mesh_terms: D000818:Animals; D002923:Cilia / Q000648:ultrastructure; D003712:Dendrites / Q000648:ultrastructure; D004848:Epithelium / Q000648:ultrastructure; D008854:Microscopy, Electron; D008871:Microvilli / Q000648:ultrastructure; D008974:Mollusca / Q000648:ultrastructure*; D009132:Muscles / Q000294:innervation; D012679:Sense Organs / Q000648:ultrastructure; D011984:Sensory Receptor Cells / Q000648:ultrastructure*