What occurs to the ovum after it is fertilized by a sperm?

After fertilization by sperm, the ovum undergoes a significant transformation as it embarks on its journey toward implantation. Specifically, the fertilized ovum, now referred to as a zygote, begins to divide and develop as it travels down the fallopian tube toward the uterus. During this journey, a series of cell divisions occur, transforming the zygote into a blastocyst.

Upon reaching the uterus, the blastocyst seeks out a suitable spot on the uterine lining, known as the endometrium, to implant itself. This process of implantation is crucial as it establishes the connection necessary for nutrient and gas exchange between the developing embryo and the maternal blood supply. Successful implantation marks the beginning of pregnancy, allowing for further development of the embryo.

This understanding of the ovum's journey highlights the importance of the fertilization process and subsequent implantation in establishing a viable pregnancy, differentiating it clearly from other options like disintegration, remaining in the ovaries, or being expelled from the body, which do not accurately reflect the biological processes following fertilization.