Early embryonic devlpmnt

Early embryonic development

1. E arly e MBRYONIC DEVELOPMENT Presented by Aswathy A Akshaya Anil S 3 M.Sc Biochemistry Dept.of Biochemistry Kerala University

2. EARLY EMBRYONIC DEVELOPMENT Embryonic development is when the embryo is formed and develops. It starts with the fertilization of a egg , which after is called a zygote. The zygote goes through rapid divisions Process is known as embryogenesis

3. Events in embryonic development Cleavage Gastrulation Org a no g en e sis

4. 1,cleavage The single celled zygote undergoes a period of rapid cell division without growth to produce a ball of cells .

5. BLAST ula A hollow ball of cells are formed called a blastula . The blastula consist of many smaller cells called blastomeres . The blastula has a hollow part that is filled with fluid and is called a blastocoel .

6. TYPES OF CLEAVAGE 1) Meroblastic cleavage incomplete division of the egg . occurs in species with yolk-rich eggs only part of the zygote undergoes cleavage happens in eggs due to the large volume of y olk 2) Holoblastic cleavage complete division of the egg . occurs in species eggs have small amount of yolk entire zygote undergoes cleavage

7. E arly embryonic development in which the cells of a blastula rearranges into a three-layered embryo, called a gastrula . 2,GASTRULATION

8. Germ layer theory Pander(1817): T rilaminar condition of chick balstoderm. Primary germ layers: only ectoderm & endoderm ( Radiata). only germ layers in primitive metazoan stage. Secondary germ layers: third layer( mesoderm) is also present. ( Bilateria , Triploblastica ).

9. 3,ORGANOGENESIS Series of organised integrated process that transform an amorphous mass of cells into complete organ from the germ layers

10. 3,ORGANOGENESIS

11. EMBRYONIC DEVELOPMENT S

12. REFERENCES Developmental biology-7 th edition-Scott F. Gilbert A manual of Developmental biology-Vijayakumaran Nair.