Capacitated spermatozoa

Fertilization is the fusion of the sperm and ovum. The sperm head binds to the plasma membrane of the egg (oolemma), and the entire spermatozoon enters the cytoplasm of the ovum. Only capacitated spermatozoa with intact acrosomes can enter and pass through the cumulus oophorus. The acrosome is a membrane-bound, cap-like structure covering the anterior portion of the sperm nucleus. The acrosomal reaction is the release of materials that lyse the glycoprotein coat (zona pellucida) surrounding the ovum. This is necessary for fertilization to take place. Before undergoing the acrosomal reaction, sperm go through a type of hypermotility called hyperactivation. The... 

What does happen to spermatozoa that reach the post-capacitated/ chemotactic stage Two facts are known about such spermatozoa. First, they have intact acrosomes, as evident from the observation that the level of acrosome-less spermatozoa does not increase during the continuous replacement of capacitated spermatozoa [29]. Second, once a cell becomes post-capacitated/chemotactic, it is a dead end the cell cannot... 

In view of the notion that chemotaxis is required for the selection of capacitated spermatozoa, faulty precontact sperm-egg communication may be one of the causes of male infertility, female infertility, or both. It is reasonable that, in the future, chemotaxis may be exploited as a diagnostic tool for sperm quality and male infertility and may be used as a biological sperm-selection procedure before in vitro fertilization, especially before intracytoplasmic single sperm insertion or for intrauterine insemination. Moreover, the chemotactic activity of a follicular fluid may be an effective way to monitor the possible effects of different ovulation induction protocols on the maturational status of oocytes aspirated for in vitro fertilization [2]. On the other hand, interference vwth sperm chemotaxis may represent an exciting new approach to contraception. 

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