BLG 10A/B Lecture Notes - Lecture 28: Zona Pellucida, Acrosome, Pronucleus
21 Apr 2020
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Gestation period: time from last menstrual period until birth (~280 days) Sperm"s chromosomes combine w/ those of secondary oocyte to form fertilized egg (zygote) Before fertilization can occur, sperm must reach secondary oocyte: oocyte viable for 12 to 24 hours. Sperm viable 24 to 48 hours after ejaculation. Coitus must occur no more than 2 days before & at least 24 hours after ovulation. Sperm transport & capacitation: most ejaculated sperm do not make the 12-cm trip through the uterus and to the uterine tube to join w/ egg. Some leak out of vagina, destroyed by acidic vaginal environment, fail to make it through cervix, dispersed in uterine cavity or destroyed by phagocytes. Sperm must be capacitated before they can penetrate oocyte enhance motility & cell membranes must become fragile enough to release hydrolytic enzymes. Secretions of female tract help to weaken and thin out acrosome membrane.
