Question

Given diagrams showing the different stages in the process of fertilization of an egg in the human female reproductive tract.
Study the diagram and answer the question.
Where does fertilization normally take place?
What is ‘Implantation’ that follows fertilization?

Answer 1

Hint: Fertilization is the process of fusion of sperm into the ovum or egg cell which occurs in the fallopian tube then acrosomal reaction (i.e. the plasma membrane of secondary oocyte and sperm fuses to pass the content of sperm) takes place. After the sperm fuses with the oocyte or egg cell cortical reaction (i.e. prevention of fertilized egg cell or oocyte by getting fertilized with other sperms) takes place. Implantation occurs on the inner wall of the uterus.

Complete answer:
In the given diagram, the correct order is from (d), (c), (b), and (a) in which (d)- it shows that an egg cell is containing nucleus,
(c)- it shows that the egg cell is surrounded by number of sperms which are trying to fuse into it i.e. egg cell, (b)- it shows the successful fusion of sperm with the egg cell, (a)- it shows the two nucleus from which one is of egg cell and another one is of sperm cell.
Fertilization is the process of fusion of sperm with oocyte or egg cell and it takes place in the fallopian tube which connects the ovary and uterus.
Implantation (i.e. a stage of pregnancy) is followed by fertilization which occurs due to the enzymes secreted from trophoblast cells (i.e. a layer of tissue on the outer side of the blastula which provides nourishment to embryo and forms a major part of placenta) which digests the blood vessels and tissues of inner wall of the uterus. Implantation of embryo or fertilized egg cell takes place in the endometrium of the uterus. The process of fertilization and implantation generally takes approximately 7-11 days.

Note: Fertilization and Implantation process is followed by several steps that are: 1.Oocyte-produced by the ovaries,
2.Fertilization,
3.Zygote formation,
4.Cleavage,
5.Formation of Morula,
6.Blastocyst formation,
7.Implantation.
The first sperm which enters or fuses with the egg cell successfully only that sperm further helps in this process. Once the sperm enters the egg cell then its tail gets disintegrated automatically.