Image of human egg being fertilized from the British Broadcasting Corporation - Education, BBC
Embryonic Stem Cell lines may be generated at this point.
|Ovulation Occurs in Two Phases
The first phase of the ovulation cycle is the follicular phase. It begins the first day of the last menstrual period (LMP) and stops at the next ovulation. This phase varies greatly for each woman.
The second phase is the luteal phase. It begins the day of ovulation and lasts until the next menstrual cycle begins. Governed by hormone release, it follows a more regular timeline of between 12 to 16 days following ovulation.
The day of ovulation determines the length of a menstrual cycle. The common belief that stress can affect the timing of a period is half true. Stress can affect ovulation which then affects hormone release which begins the next menstrual period ; but, stress around the time of an expected period will not make it late - that date was decided 12-16 days earlier.
What Is Going On Here?
The blastocyst embryo with its two cell types: the inner cells that can initiate all cells of the body, and the outer cells destined to become the placenta, is the source of embryonic stem cells (esc).
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Professor of Regenerative Medicine,
Embryonic Stem Cells And Stem Cell Technology,
The Naked Scientists Interviews