Nuclear Vacuole

Structure and/or Key Feature(s)

The nuclear vacuoles are thought to develop as a consequence of incomplete chromatin condensation during the process of spermatogenesis. They have been observed in 90% of structurally and functionally normal sperm, and differ in number, size, and location. Some can be so large that they contort the shape of the sperm head (Guraya, 2012).

The nuclear vacuoles can exist in both singular and multiple forms and contain materials such as granular cytoplasmic substances and remnants of nuclear and plasma membranes.

The number and size of nuclear vacuoles are indicative of the maturity or immaturity of the nucleus of the sperm. Large vacuoles are mostly observed in mature sperm (Toshimori, 2009).

Anatomical Relations

Nuclear vacuoles are situated within the nucleus of the sperm.

Function

The function of nuclear vacuoles is not well known. It is still unclear whether or not they have an effect on fertilization. However, since nuclear vacuoles are associated with incomplete chromatin condensation, they may be associated with abnormal sperm morphology (Komiya et al, 2014).

References

Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.

Guraya, S. S. (2012) Biology of Spermatogenesis and Spermatozoa in Mammals. Springer Berlin Heidelberg.

Komiya, A., Kawauchi, Y., Kato, T., Watanabe, A., Tanii, I. & Fuse, H. (2014) Sperm nuclear vacuoles in relation to acrosome reactions and sperm motility. ScientificWorldJournal, 2014, 178970.

Toshimori, K. (2009) Dynamics of the Mammalian Sperm Head: Modifications and Maturation Events From Spermatogenesis to Egg Activation. Springer.