Pregnancy Notes During sex, semen, which contains sperm, is ejaculated from the male’s penis into the vagina. (**Note: Some sperm can exit the penis before ejaculation without the male’s knowledge.)
Sperm can survive for 48 hours in the female reproductive tract. Fertilization, when the sperm and the egg join, can occur a few days before ovulation to a few days after ovulation. • About 300 million sperm are released into the vagina during sexual intercourse.
Although only one sperm cell penetrates the egg, several hundred sperm cells are needed for the process. • The sperm cells act as a team to bombard the egg. They release a special enzyme called acrosome that weakens the plasma that surrounds the egg. • Eventually, when the plasma is weak enough, one sperm cell will be able to penetrate the egg, and the egg is now, fertilized.
The fertilized egg is called the zygote. • The zygote travels down the Fallopian tube and divides into two cells, and then into four cells, and then into 16 cells, and so on. • This mass of cells implants into the endometrium, the lining of the uterus, and the embryo now begins to develop and grow into the child.
Pregnancy Scenario Example: Alexander and Monica have protected sex by using a condom. The condom doesn’t break. 1) Will Monica get pregnant? 2) Explain your reasoning.