Question

Prelab Questions 1. Gastrulation begins at what end of the embryo? 2. What is the primitive streak? 3. What is Hensen's node? 4. What is Neurulation? What is the final outcome once neurulation is complete?

Answer 1

Ans 1) Gastrulation is basically the process of cellular reorganization in the embryo from blastula and it leads to formation of three germ layers – ectoderm, endoderm and mesoderm. The process of gastrulation starts from inner cells or side of the embryo and gradually get organized into germ layers forming all organs and tissues. It generally starts from the dorsal end of embryo.

Ans) The primitive streak is basically the embryonic structure which is formed from the blastula and the structure starts from dorsal side and extends to the caudal side of the embryo. This also helps in the formation of germ layers. It basically forms blastula most commonly in avian, mammals and reptiles during their early stage.

Ans) Hensen node is the primitive knot and is the site where the process of gastrulation starts from. It is located in the anterior side of primitive blastula from which gastrulation starts and the cells migrate towards anterior side forming side layers.

Ans) The neurulation is the process which helps in folding and transforming the neural plate into neural tube. The process starts at notochord which leads to production of CMS and forms the neural plate. These neural plates form amongst themselves and form the neural tube. The final result of neurulation is that it differentiates into spinal cord and the brain.