In bone tissue, the extracellular matrix primarily contains proteins and materials that provide structure and support. Among the options you've provided, the following can be found in the extracellular matrix of bone tissue:
Collagen
Collagen is a major component of the extracellular matrix in bone, contributing to its tensile strength and structural integrity.
The other options are not part of the extracellular matrix:
- Chondrocytes are the cells found in cartilage, not bone.
- Osteocytes are the cells embedded in the bone matrix, but they are not considered part of the extracellular matrix itself.
- Endosteum is a membrane that lines the inner surface of the bone, not a component of the extracellular matrix.
So, the correct answer is Collagen.