Flashcards in First Week of Development Deck (17):
Where does fertilization occur?
the ampulla of the uterine tube
When can a sperm fertilize an egg?
only after undergoing capacitation and acrosome reaction
period of conditioning that takes place in female reproductive tract lasting 7 hours
induced by zona proteins after the sperm binds to the zona pellucida, this process releases enzymes that allow the sperm to penetrate the zona pellucida
How many phases does fertilization have?
Phase 1 of fertilization
passage of sperm through the corona radiate of the oocyte
Phase 2 of fertilization
penetration of the zona pellucida, the release of acrosomal enzymes allows the sperm to penetrate the zona pellucida and come in contact with the plasma membrane of the oocyte
Phase 3 of fertilization
fusion of the plasma cell membranes of the oocyte and sperm, sperm head and tail enter the oocyte
Phase 4 of fertilization
completion of the second meiotic division of the oocyte- forms the female pronucleus and the second polar body
Phase 5 of fertilization
formation of the male pronucleus- the tail degenerates and the nucleus of the sperm enlarges, DNA replication occurs
Phase 6 of fertilization
breakdown of the pronuclear membranes and restoration of diploid number of chromosomes
division of the zygote begins approx. 30 hours after fertilization
What are the cells that become smaller during mitotic division of the zygote called?
the 16 to 32 cell stage
around day 4 the morula enters the uterus, uterine fluid penetrates through the zona pellucida to the intercelluar space of the inner cell mass, the fluid filled space is called the blastocystic cavity
Blastomeres are seperated into two parts
Inner cell mass is the embroblast that gives rise to the embryo proper, and the outer cell mass or tropoblast that forms the placenta