Sperm capacitation occurs in -

Ans is 'b' i.e., Fallopian tubes Fallopian tune is the main site o 1% of sperms deposited in the vagina enter the cervix o Movement of sperm from the cervix to the uterine tube occurs by muscular contractions of the uterus and uterine tube and very little by their own propulsion. o Spermatozoa are not able to fertilize the oocyte immediately upon arrival in the female genital tract but must undergo (1) capacitation and (2) the acrosome reac- tion to acquire this capability. o Capacitation is a period of conditioning in the female reproductive tract that in the human lasts approximately 7 hours. o Conditioning during capacitation occurs in the fallopian tube and involves epithelial interactions between the sperm and the mucosal surface of the tube. o During this time, a glycoprotein coat and seminal plasma proteins are removed from the plasma membrane that overlies the acrosomal region of the spermatozoa. o Only capacitated sperm can pass through the corona cells and undergo the acrosome reaction. o The acrosome reaction, which occurs after binding to the zona pellucida, is induced by zona proteins. This reaction culminates in the release of enzymes needed to penetrate the zona pellucida, including acrosin and trypsin like substances.