SCI227 Lecture Notes - Lecture 19: Chorionic Villi, Corpus Luteum, Yolk Sac
Document Summary
The secondary oocyte and the sperm unite a mature ovum is the secondary oocyte is released from the ovary occurs in the fallopian tube formed and then it becomes a fertilized ovum (zygote) The zygote is a single cell that has 46 chromosomes. Out of the 500 million sperm ejaculated only a few will reach the fallopian tube. It takes 3-5 days for the fertilized egg to travel from the fallopian tube to the uterus. During that time the fertilized egg undergoes a process called cleavage. The cell number doubles with each division but does not increase in size. A morula is of a solid ball (morula) of 16-32 cells. It continues till a hollow ball of cells (blastula/ blastocyst) is formed consists of two layers of cells: outer, inner, the outer forms: Extraembryonic structures (e. g. chorion, amnion : the inner forms: the embryo. Involves the blastocyst attaching to the endometrium in the uterus: implantation.
