From which embryonic structure do the cells of the nucleus pulposus originate?

From which embryonic structure do the cells of the nucleus pulposus originate?

• A. Notochord
• B. Neural tube
• C. Somite
• D. Neural crest

Answer: (A)

From the notochord. The notochord remains inside the developing intervertebral discs and its cells persist as the nucleus pulposus, forming the gelatinous center of the disc as surrounding mesenchyme forms the annulus fibrosus and vertebral bodies. In contrast, neural tube becomes the spinal cord, somites give rise to vertebrae and muscle, and neural crest contributes to peripheral nerves and other tissues, not the disc core.

From the notochord. The notochord remains inside the developing intervertebral discs and its cells persist as the nucleus pulposus, forming the gelatinous center of the disc as surrounding mesenchyme forms the annulus fibrosus and vertebral bodies. In contrast, neural tube becomes the spinal cord, somites give rise to vertebrae and muscle, and neural crest contributes to peripheral nerves and other tissues, not the disc core.