The outer layer of the annulus fibrosus primarily consists of which material?

The outer layer of the annulus fibrosus primarily consists of collagen. This fibrous ring surrounds the nucleus pulposus in intervertebral discs and plays a critical role in providing structural support and stability to the spine. The collagen within the annulus fibrosus is organized in concentric layers, which helps withstand the tensile forces exerted during spinal movement. This arrangement not only contributes to the mechanical strength of the disc but also helps to maintain its shape and integrity.

Other components, such as polysaccharides, elastin, and laminin, may be present in various tissues in the body, but they do not constitute the primary material in the annulus fibrosus. While polysaccharides are important in the extracellular matrix and play a role in hydration and nutrient transport, they are not the main structural component. Elastin contributes to the elasticity of tissues, particularly in areas like the skin and lungs, but is not predominant in the annulus fibrosus. Laminin is a protein found in the basal lamina and relates to cell adhesion and differentiation, but again, it does not play a significant structural role in the annulus fibrosus. Hence, collagen is indeed the predominant material that provides the necessary strength and support in this