Nucleus pulposus

Nucleus pulposus is the jelly-like substance in the middle of the spinal disc. It is the remnant of the notochord. It functions to distribute hydraulic pressure in all directions within each disc under compressive loads. The nucleus pulposus consists of chondrocytes, collagen fibrils, and proteoglycan aggrecans that have hyaluronic long chains which attract water. Attached to each hyaluronic chain are side chains of chondroitin sulfate and keratan sulfate.