How does the Embryo Develop?
Embryo development is a process that follows fertilisation. The embryo, before reaching the uterus, undergoes a series of divisions that help in its growth and development. This process of development of the embryo is called Embryogenesis which is as follows:
- Fertilisation results in the formation of a zygote in the Fallopian tubes of the female reproductive system.
- The fertilized egg cell will divide to form two cells, followed by four and so on. This results in the formation of a ball-like structure which contains many cells inside it.
- When the cell number in the ball-like structure is sixteen, it is called Morula. The morula further divides to form a structure called Blastula which is a stage where the cells arrange themselves to form a hollow mass structure. The cells align themselves to the ends and leave a cavity within, which gets filled with fluid.
- The next stage of development is called Blastocyst. It is a stage where the embryo will have cells that have got differentiated and will even differentiate further with the help of the process called Differentiation. In this process, one cell gets differentiated from the other cells in its vicinity. Thus, a whole new variety of cells are formed from these differentiated ones, after successive divisions.
- The blastocyst is now a mass containing differentiated cells. As it grows further, the body of the embryo begins to develop. It then enters the next stage called Implantation. In this stage, the embryo attaches itself in the uterus at a fixed position for deriving nutrition, giving away wastes and exchanging gases. This place of attachment is an organ called the Placenta which connects the baby with its mother.
- The embryo is ready to grow into a baby. The stage where the organs of the baby’s body start developing, such that they can be identified, is called the Foetal Stage and the embryo in this stage is called a Foetus.
- The foetus grows in the uterus after taking the required amount of time. When the growth is completed, the child is ready to be born.
Morula, Blastula, Blastocyst and Cell showing Differentiation process
Morula, Blastula, Blastocyst and Cell showing Differentiation process
Do the embryos of all organisms develop in the same way?
The development of embryos in the organisms takes place in different ways. Based on the location where the embryo develops, there are two types of embryo development:
Viviparity
- In this type, the foetus grows inside the mother’s body.
- It results in the mother giving rise to the young one directly.
- Organisms exhibiting this type of embryonic development are called Viviparous
organisms. - For example, humans, cows, monkeys etc.
Oviparity
- In this type, the foetus grows outside the mother’s body.
- The mother lays eggs and the young ones emerge from these eggs.
- Organisms exhibiting this type of embryonic development are called Oviparous organisms.
- For example, frogs, snakes, hens etc.