Ciliary Movement and Coordination in Ciliates

Abstract

Publisher Summary In certain ciliates and especially in metazoan epithelia, ciliary activity produces a displacement not of the cells themselves but of particles in the environment. Activity under these circumstances becomes progressively more stereotyped and restrictively adapted to special needs. The autonomous movement of the individual cilium is not rotatory but simply pendular. Thus in a given ciliated field, movement occurs in the same plane during all phases of the beat. In an intact epithelium, ciliary movement is metachronal, but it seems to be synchronous in isolated ciliated cells. Ciliated epithelia of many metatoa operate under the secondary control of the nervous system, and this control is usually of an inhibitory nature. In the activity of metazoan ciliated epithelia another tendency, encountered in rudimentary form in some ciliates, seems to accompany the stabilization of the beating plane: the role of elastic elements as antagonists of contractile forces becomes more significant in the beating cycle in some epithelia. The chapter discusses some of the fragmentary and scattered data on the mechanism of ciliary activity. Two principal types of ciliary movement must be recognized: in one the planes of the effective and recovery phases of beat are identical; in the other these planes are different. Both types comprise several varieties, among which some may differ even as to the physical basis of the effective stroke.