Primary neurulation forms which CNS structure?

Primary neurulation forms which CNS structure?

• A. The neural tube forms the brain and spinal cord.
• B. The caudal spinal cord from a caudal cell mass.
• C. Neural crest cells.
• D. The neural plate.

Answer: (A)

Primary neurulation builds the neural tube, which becomes the brain and spinal cord. During this process, the neural plate (a thickened region of ectoderm) folds inward and closes to form a hollow tube that runs along the length of the embryo. This neural tube then differentiates to become the central nervous system: the cranial end develops into the brain and the remainder forms the spinal cord. The caudal spinal cord from a caudal cell mass is produced later by secondary neurulation, not primary neurulation. Neural crest cells arise at the edges of the neural folds and contribute to many structures outside the CNS, and the neural plate is the pre-neurulation tissue. So the neural tube formed by primary neurulation is what gives rise to the brain and spinal cord.

Primary neurulation builds the neural tube, which becomes the brain and spinal cord. During this process, the neural plate (a thickened region of ectoderm) folds inward and closes to form a hollow tube that runs along the length of the embryo. This neural tube then differentiates to become the central nervous system: the cranial end develops into the brain and the remainder forms the spinal cord. The caudal spinal cord from a caudal cell mass is produced later by secondary neurulation, not primary neurulation. Neural crest cells arise at the edges of the neural folds and contribute to many structures outside the CNS, and the neural plate is the pre-neurulation tissue. So the neural tube formed by primary neurulation is what gives rise to the brain and spinal cord.