Fasciola hepatica: a transmission and scanning electron microscopical study of the apical surface of the gastrodermal cells.

Abstract

SummaryThe ultrastructure of the apical surface of the gastrodermal cells of Fasciola hepatica has been investigated by transmission (TEM) and scanning electron microscopy (SEM). The surface is composed of triangular or rhomboidal lamellae which may be subdivided at their margins. The lamellae may have a smooth or wrinkled surface and apical microvilli of varied length and number. Spherical bodies may be attached to the sides or tips of the lamellae.The lamellae of individual cells are grouped to form either a series of overlapping, concentrically arranged leaflets or a series of sinuous lamellae running parallel with the cell's long axis. Lamellae may also divide, anastomose, or cross from one cell to an adjacent cell.The lamellae have an internal skeleton consisting of laterally orientated ‘fibres’ which are more or less evenly spaced and parallel with the cell's apical plasma membrane. There is some evidence that the ‘fibres’ are composed of a number of very small tubules in a dense matrix. The ‘fibres’ are connected to the plasma membrane and to each other by dense amorphous material.