The functions of hyperactivation may fit together to create the following scenario. Sperm that enter the oviduct bind to the mucosal epithelium. Near the time of ovulation, hyperactivation helps them to detach from the epithelium, escape mucosal pockets, and move through oviductal mucus. As sperm reach the ampulla, frequent changes in direction may enable them to encounter the cumulus mass. Then, hyperactivation assists them in penetrating the cumulus matrix and, after acrosome reacting, the zona pellucida. A factor or factors in the periovulatory oviduct or follicular fluid may induce hyperactivation by raising intracellular calcium levels in sperm. Knowledge of mechanisms regulating hyperactivation may be used to develop new clinical tests for fertility of semen samples.