In early embryonic development, the process of gastrulation is responsible for forming the three primary germ layers. The ectoderm, mesoderm, and endoderm are all derivatives of the gastrula. This process can be divided into two different stages: blastula and gastrula. In this blog post, we will explore the difference between these two stages.
What is Blastula?
The blastula is an early stage of embryonic development in many animals, characterized by a sphere of totipotent cells surrounding a fluid-filled cavity. The Blastula stage typically follows gastrulation, during which the Blastula forms from the invagination of the embryo. In some cases, Blastula formation may occur via budding or regeneration.
The Blastula is usually transient, giving rise to the more differentiated Gastrula stage. Depending on the species, Blastula Stage may last from several hours to several days. Studies of Blastula development have provided insight into numerous aspects of cell biology and developmental genetics.
What is Gastrula?
Gastrula is a developmental stage that marks the beginning of gastrulation, a process by which the three germ layers of the embryo are formed. Gastrulation occurs during the second week of embryonic development, after the formation of the blastula. The Gastrula stage is characterized by the invagination of cells at the blastula surface, which results in the formation of a hollow, cup-shaped structure called the gastrula. The cells that invaginate into the gastrula will go on to form the three germ layers: ectoderm, mesoderm, and endoderm. These germ layers will give rise to all of the tissues and organs of the adult body. Gastrulation is an essential step in embryonic development, and without it, a normal, healthy child could not be born.
Difference between Blastula and Gastrula
The difference between Blastula and Gastrula is Blastula is a hollow sphere of cells with a single opening, the blastopore, at one end while Gastrula is a gastrula with three primary germ layers.
- The Blastula stage occurs after cleavage and before gastrulation in embryonic development. Cleavage is when the zygote undergoes mitotic cell divisions to form a multicellular blastula.
- The blastula stage is a critical phase of embryonic development that leads to gastrulation. Gastrulation is when the three primary germ layers – ectoderm, mesoderm, and endoderm – are formed from the blastula.
- The Blastula stage is characterized by blastomeres, which are cells that make up the Blastula. Blastomeres are arranged in a layer around the central cavity of the Blastula, called the Blastocoel.
The innermost layer of cells lining the Blastocoel is called the hypoblast while the outer layer of cells is called the Epiblast. The hypoblast gives rise to endoderm while the epiblast gives rise to ectoderm and mesoderm. During gastrulation, Cells migrate through the Blastopore to form the three primary germ layers.
Conclusion
The blastula and gastrula are two very important stages in the development of a fertilized egg. They are both characterized by different cell types and structures that will eventually give rise to all the tissues and organs in an organism. While the blastula is still relatively simple, the gastrula contains some of the first organ rudiments. It’s amazing to think about how much can change in such a short amount of time!
