Tail

Abstract

The motor apparatus of the spermatozoon tail is the axoneme or axial filament complex which consists of the usual central pair or axial fibrils (or microtubules) surrounded by an inner row of nine evenly spaced doublet microtubules, each with two rows of arms that project towards the adjacent doublet tubule, one row of radial spokes that radiate inwards towards the central pair of microtubules, and an outer ring of nine coarse longitudinal fibres (Figs. 45, 57 and 61) (Fawcett 1975b, Harding et af. 1979, Linck 1979, Satir 1979, Amelar et al. 1980, Bae and Kim 1981, Holstein and Roosen-Runge 1981). Actually, all the structural components of the flagellum, which include the connecting piece, 9 + 2 axoneme, fibrous sheath, and outer dense fibres, are structurally interlocked into one functional unit. There occur some variations in the size of coarse filaments (usually nos. 1, 5, 9). A central sheath, made up of projections has been described surrounding the two central tubules (Fig. 66). It is connected by nine spokes, radial links to the nine doublets, which are also connected to each other by the inter-doublet links (Fig. 66).