ANATOMY

Detailed explanation-1: -Contact between the egg and sperm is random. Once the egg arrives at a specific portion of the tube, called the ampullar-isthmic junction, it rests for another 30 hours. Fertilization-sperm union with the egg-occurs in this portion of the tube. The fertilized egg then begins a rapid descent to the uterus.

Detailed explanation-2: -During fertilization, the sperm and egg unite in one of the fallopian tubes to form a zygote. Then the zygote travels down the fallopian tube, where it becomes a morula. Once it reaches the uterus, the morula becomes a blastocyst. The blastocyst then burrows into the uterine lining-a process called implantation.

Detailed explanation-3: -When a fertilized egg has implanted in the uterus, the group of cells that will become a baby is called an embryo. A developing, fertilized egg is known by several names within the first 2 weeks after conception, including zygote, morula (day 4), and blastocyst (day 5).