Final answer:
The egg travels through the fallopian tube for about seven days after ovulation. Fertilization, if it occurs, happens within this timeframe as sperm can survive a few days post-ovulation. The embryo then spends approximately 72 hours in the fallopian tube before moving towards the uterus.
Step-by-step explanation:
After ovulation, the egg, or oocyte, is released from the ovary and is swept into the fallopian tube by the fringelike ends called fimbriae. The egg then begins its journey to the uterus. This passage through the fallopian tube typically takes about seven days. If sperm are present, fertilization may occur during this transit, usually within the fallopian tube itself. It is within these fallopian tubes that the sperm has the potential to meet and fertilize the egg. Here, fertilization is possible for up to a few days post-ovulation due to the sperm's ability to survive for this duration. The resulting embryo continues its development in the fallopian tube for approximately 72 hours before continuing towards the uterus.
The beginning of the ovarian cycle is marked by the follicular phase, during which follicles on the surface of the ovary grow under the influence of FSH and LH, leading up to ovulation and the egg's release. The hormones estrogens, and a low level of progesterone, support the egg's maturation and maintain the endometrium, potentially preparing for pregnancy. If the egg is not fertilized and pregnancy does not ensue, the cyclical shedding of the endometrial lining occurs, known as menstruation.