Which statement about the nucleus pulposus is true?

Which statement about the nucleus pulposus is true?

• A. A central nucleus pulposus that is filled with a gelatinous substance
• B. A ring composed of bone tissue
• C. A central gelatinous substance in the nucleus
• D. Outer fibrous ring

Answer: (A)

The central feature being tested is that the nucleus pulposus is the gel-like core of the intervertebral disc. It sits in the center of the disc and is filled with a gelatinous, water-rich substance rich in proteoglycans, which gives the disc its ability to cushion and spread loads evenly when the spine is compressed. The surrounding ring is the annulus fibrosus, which is fibrous tissue—not bone, and it forms the outer boundary. Therefore, the statement that the nucleus pulposus is a central gelatinous substance is the correct description. With aging, this gelatinous core can lose water and become firmer, contributing to disc degeneration, but its defining trait remains its central, gelatinous nature.

The central feature being tested is that the nucleus pulposus is the gel-like core of the intervertebral disc. It sits in the center of the disc and is filled with a gelatinous, water-rich substance rich in proteoglycans, which gives the disc its ability to cushion and spread loads evenly when the spine is compressed. The surrounding ring is the annulus fibrosus, which is fibrous tissue—not bone, and it forms the outer boundary. Therefore, the statement that the nucleus pulposus is a central gelatinous substance is the correct description. With aging, this gelatinous core can lose water and become firmer, contributing to disc degeneration, but its defining trait remains its central, gelatinous nature.