Question

For fertilization to take place, why must sexual intercourse take place in the period that starts two days before and ends one day after ovulation?

a. Increased sperm motility
b. Enhanced hormonal secretion
c. Optimal conditions for egg fertilization
d. Improved uterine lining receptivity

Answer 1

Sexual intercourse is most effective for fertilization when it happens around ovulation; sperm can survive for a few days in the female reproductive tract, but the egg is viable for only about 24 hours. The body also undergoes changes to assist in sperm survival and capacitation.

Step-by-step explanation:

For fertilization to take place, sexual intercourse is most effective when it occurs in the period starting two days before and ending one day after ovulation. This timing ensures that sperm are present in the fallopian tubes when the egg is released from the ovary. Sperm can survive for 3-5 days in the female reproductive tract, which allows for the possibility of fertilization if intercourse happens a few days before ovulation. The egg, on the other hand, can only survive for about 24 hours after being released.

Therefore, intercourse after this time frame is unlikely to result in fertilization. Additionally, during this fertile window, the body undergoes a series of changes, including the release of cervical mucus that is thinner and more alkaline, which promotes the passage of sperm and provides a hospitable environment for them. Furthermore, sperm undergo a process called capacitation, which enhances their motility and ability to penetrate the egg.

Answer 2

Sexual intercourse must be timed closely with ovulation to optimize the chances of fertilization, due to the survival rates of both sperm and the egg, and the process of capacitation that the sperm must undergo in the female reproductive tract.

Step-by-step explanation:

For fertilization to take place, sexual intercourse needs to be timed with ovulation because this is when the conditions are optimal for egg fertilization. Ovulation occurs around the midpoint of a menstrual cycle, generally on day 14 of a 28-day cycle, wherein the egg is released and travels into the fallopian tube. Sperm need to be present in the fallopian tube for fertilization to occur. Since sperm can survive for 3-5 days in the reproductive tract but an egg only survives for about 24 hours after being released, the best chance for fertilization occurs when intercourse takes place within a window of two days before and up to one day after ovulation.

The endometrial lining also undergoes changes to help sperm reach the oocyte, such as becoming more vascular and the cervical mucus becoming thinner. These changes increase the chances of sperm surviving the harsh conditions of the female reproductive tract and reaching the oocyte.

Capacitation is a crucial process that sperm must undergo, which improves their motility and ability to penetrate the oocyte. This process is facilitated by the fluids in the female reproductive tract that prime the sperm, thinning their membrane for better enzyme release necessary to penetrate the egg. Once fertilization occurs, the newly formed zygote (the fertilized ovum) will become resistant to penetration by any other sperm.