KNES 191B Lecture Notes - Lecture 12: Zona Pellucida, Corona Radiata, Inner Cell Mass
16 Aug 2016
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Document Summary
Extends from fertilization to eighth week of development: fertilization: merging of genetic information from sperm and secondary oocyte (egg), sperm swim from the vagina to the cervix using their tails (flagella). From vagina, to uterus, to uterine tubes (fallopian tubes). The sperm is able to travel so far because of contractions of the walls of these structures. To fertilize an egg, sperm must penetrate the corona radiata and the zona pellucida: corona radiata: granulosa cells, zona pellucida: glycoprotein layer outside of the egg"s plasma membrane; shell of the egg that serves as protection. When they are bound together, acrosomal enzymes are released, which digest a path to the zona pellucida. Once the egg is penetrated, the nuclei from the egg and sperm merge together: when the two, haploid pronuclei merge (syngamy), a diploid zygote is formed: dna is from both the sperm and eggs. The haploid nucleus in the head of the sperm is the male pronucleus.
