Final answer:
After being deposited in the vagina, sperm travel through the cervix, uterus, and into the fallopian tubes where fertilization with an egg typically occurs. On this journey, sperm undergo capacitation, which increases their chances of successful fertilization.
Step-by-step explanation:
Assuming a couple has just consummated the sex act and the sperm have been deposited in the vagina, to achieve fertilization, the pathway of the sperm through the female reproductive tract is as follows:
- Vagina
- Cervix
- Uterus
- Fallopian tube (where fertilization typically occurs)
During intercourse, sperm are ejaculated into the vagina and must travel through the cervix, which is the entrance to the uterus. After swimming through the uterus, sperm enter the fallopian tubes, where fertilization usually happens if an ovulated oocyte (egg) is present. The egg, once fertilized, becomes an embryo and begins its journey to the uterus for implantation.
It's important to note several challenges that sperm face on this journey. The acidic environment of the vagina, cervical mucus, and the immune defense of the uterus all act to significantly reduce the number of sperm that reach the egg for potential fertilization. Capacitation is a process that sperm undergo within the female reproductive tract that increases their motility and prepares them to penetrate the oocyte.