PSL300H1 Lecture Notes - Lecture 33: Zona Pellucida, Corpus Luteum, Polyspermy
Document Summary
The outer coating on the sperm is removed in the uterus with changes to the cell membrane, increasing motility through synchronized movements of head and tail. The sperm must pass through cervical mucus (thinned due to estrogen), uterine cavity and the fallopian tubes. Uterine and oviduct contractions aid transport (estrogen, prostaglandins, which is part of the semen) The first sperm that fuses with the egg wins prevents a cortical reaction which prevents polyspermy (if this happened, genetic integrity would not be maintained) The sperm docks with the sperm-binding proteins on the oocyte membrane. The nucleus complete meiotic division, the second polar body is expelled and the zygote is formed. Blastocyst inner cell (embryo) and the trophoblast (placenta) Decidua produced from endometrial cells secrete several hormones and growth factors. Forms the maternal side of the placenta. Cytotrophoblast & syncytiotrophoblasts (helps with the invasion of the endometrium, for the placenta and secretes most of the hormones)
