Embryology Further Development of Embryonic Disc Essay Question And Answers

Question 1. Formation, functions and fate of notochord.
Answer:

• The notochord is a midline structure, that develops between the cranial end of (he primitive streak and the caudal end of the prochordal plate.

Formation:

• The cranial end of the primitive streak becomes thickened to form primitive knot/node,
• A depression appears in the centre of it called blastopore.
• Cells in the primitive knot multiply and pass cranially upto caudal margin of the prochordal plate to form solid cord called notochordal process.
• After the formation of the blastopore, its cavity extends into notochordal process and converts ft Into notochordal canal.
• Its cells become mixed up with the endodermal cells.

Read And Learn More: BDS Previous Examination Question And Answers

• Notochordal canal is separated from yolk sac.
• Notochordal canal communicates with amniotic cavity.
• Gradually the walls of the canal become flattened forming notochordal plate.
• This process is reversed so that the plate assume the shape ofa tube.
• The proliferation of cells of this tube converts it into solid rod called definitive notochord.