Acrosome Phase

Spermatids in the acrosome phase are termed Sc. It is during the acrosome phase that significant elongation of the nucleus occurs (Johnson et al., 1990). In addition, a specialized organelle, unique to spermatids, becomes evident (Fig. 4.21). This organelle, termed the manchette, is only transient. It is composed of a series of microtubules attached to each other by linking arms, and is isolated, enfolding the caudal or lower end of the now elongating

■ ii tairut rnniiMVi a-vraz-inu

■ ii tairut rnniiMVi a-vraz-inu

Plasma Membrane

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Fig. 4.21. A simplified diagram to illustrate the final stages of spermiogenesis, and the development of the flagella.

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Fig. 4.21. A simplified diagram to illustrate the final stages of spermiogenesis, and the development of the flagella.

nucleus near the developing flagellum. It then extends down to enclose the upper part of the developing flagellum. The manchette persists after elongation and remnants of it are evident in the residual body left behind after spermiation. There should be no evidence of it in mature spermatozoa, except in cases where parts of the residual body are left on mature spermatozoa due to incomplete maturation (Goodrowe and Heath, 1984; Johnson, 1991b).

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