Final answer:
The lifespan of the ovum is approximately 24 hours after ovulation, hence the statement about it lasting 168 hours is false. Day 1 of the menstrual cycle corresponds to the start of menstruation, not the release of the secondary oocyte, which typically occurs around day 14. Understanding the lifespan of the ovum is crucial for determining the window of time possible for fertilization.
Step-by-step explanation:
Lifespan of the Ovum
The statement asserting that the lifespan of the ovum is about 168 hours is FALSE. An unfertilized oocyte can survive independently for only approximately 24 hours following ovulation. This information is critical when considering the timing of fertilization, as sperm must encounter the oocyte within this timeframe to result in successful fertilization. Intercourse more than a day after ovulation will usually not result in fertilization, as the oocyte will have deteriorated.
Secondary Oocyte Release and Ovulation
Day 1 of the menstrual cycle is marked not by ovulation but by the onset of menstruation, whereas the release of the secondary oocyte occurs at the midpoint of the cycle, approximately on day 14, in a typical 28-day cycle. During the menstrual cycle, multiple processes take place, including the final maturation of tertiary follicles and ultimately the ovulation of a secondary oocyte. These events are regulated by hormones such as GnRH, LH, and FSH.