Where does capacitation of sperms occur in the reproductive tract?

After ejaculation into the female, spermatozoa move up the uterus to the isthmus of the uterine tubes where they slow down and undergo capacitation. Capacitation involves two components : increasing the motility of spermatozoa and facilitating their preparation for the acrosome reaction. From the isthmuses the capacitated spermatozoa move rapidly to the tubal ampullas, where feilization takes place. Spermatozoa attain progressive motility in the epidydimis. It involves activation of a unique set of proteins from the CatSper family, which are localized to the principal piece of the sperm tail. Ejaculation of the spermatozoon involves contractions of the vas deferens mediated in pa by P2X receptors, ligand-gated cation channels that respond to ATP. Ref: Ganong's Review of Medical Physiology, 24th Edition, Chapter 23