What is the notochord and what is its primary role in embryonic development?

The notochord is a midline mesodermal structure that develops from the primitive knot (Hensen’s node). Its primary roles are to form the central axis of the embryonic disc and induce the formation of the neural tube from overlying ectoderm.

What are the key stages in the development of the notochord?

Notochord development involves six stages: prenotochordal cell migration to form the notochordal process, canalization creating the notochordal canal, fusion and breakdown with endoderm forming a temporary neurenteric canal, plate formation into a notochordal plate, tubular conversion into a tube, and definitive notochord formation as a solid cord.

What happens to the notochord after embryonic development?

The notochord degenerates as the vertebral column grows. Its remnants persist as the nucleus pulposus of intervertebral discs and the apical ligament of the dens of the C2 vertebra.

What is chordoma and how is it related to the notochord?

Chordoma is a rare tumor that arises from notochordal remnants. It typically affects the base of the cranium or sacral region, and about 30% become malignant.

How does the notochord contribute to the formation of the vertebral column?

The notochord serves as a scaffold for the development of the vertebral column, specifically contributing to the bodies and intervertebral discs.

What structures are involved in the early formation of the notochord?

Early notochord formation involves the primitive streak, prochordal plate, and primitive knot (Hensen’s node), with cells migrating between ectoderm and endoderm.

Notochord – Embryonic Axis & Neural Induction