In a young female of reproductive age with regular menstrual cycles of 28 days, ovulation occurs around 14th day of periods. When is the first polar body extruded ?
Most of the standard text books say the first polar body is expelled just before or shortly before ovulation.
Which does not mean that it is released 24 hours before ovulation.
While still in the ovary the ovum is in the primary oocyte stage. Shortly before it is released from ovaria follicle (i.e. shortly before ovulation), its nucleus divides by meiosis and a first polar body is expelled from the nucleus of the oocyte. The primary oocyte then becomes the secondary oocyte. In this process each of the 23 unpaired of chromosomes loses one of its partners which become the first polar body that is expelled. This leaves 23 unpaired chromosomes in the secondary oocyte. It is at this time that the ovum, still in the secondary oocyte stage is ovulated into the abdominal cavity
So, first polar body is released at the time of ovulation i.e. Option “b”
24 hrs prior to ovulation
Accompanied by ovulation
48 hrs after the ovulation
At the time of fertilization