Question

What happens when eggs get fertilized?

Answer 1

Fertilization is the process in which male gamete fuses with the female gamete, resulting in formation of diploid zygote and this process is characteristic feature of sexual reproduction.

Complete Answer:
- The gametes are usually haploid and the fertilization results in the formation of diploid zygote, therefore fertilization brings back the ploidy of the organism. Fertilization requires a medium to take place.
- In the case of humans, this process takes place in the fallopian tube at the ampulla region. It is the widest part of the fallopian tube. Sperm from male enters the female reproductive tract and meets the female gamete.
- The process of sperms entering the female tract is called insemination. Before entering the female tract, the sperms get ready or dress themselves, this process is called capacitation.
- On the 14th day of menstrual cycle, the level of LH hormone increases and its concentration reaches to peak, this phenomenon is called as LH surge. It induces ovulation. The egg released from the ovary Is secondary oocyte.
- The egg passes through the fallopian tube, and if at the same time sperm reaches the ampulla region and carries out fertilization restoring the chromosome number in the zygote and simultaneously helping the secondary oocyte to complete its second meiosis.
- Zona pellucida is the primary egg membrane which is a non – cellular, transparent and gelatinous. It is formed by the egg itself, therefore called the primary egg membrane. When sperms meet ovum, it comes in contact with the zona pellucida layer of egg, and this induces certain changes in the membrane so that the entry of other sperms is prevented.
- Therefore, zona pellucida ensures that only one sperm can fertilise the ovum. The sperm contains an acrosome at its head which contains enzymes helping in fertilization of the female gamete.

Note: After fertilization, zygote undergoes cleavage to form blastomeres and during the morula stage, implantation occurs and then it is followed by development of the embryo. Fertilization causes pregnancy and this stops all the processes of menstrual cycle and no bleeding occurs for 9 months that is the gestation period.