Specialized connective/supporting tissues include cartilage and bone, which are closely related in structure and function.

• In fact, most of the bone in the body develops from a type of cartilage, as we will study in the next lab.
• Both cells and fibers are prominent in most kinds of these supporting connective tissues, but the relative rigidity of their matrices is the special quality that distinguishes them from other types of connective tissue.
• In spite of their similarities, however, cartilage is distinguishable from bone on the basis of matrix hardness, density and avascularity.
• Unlike cartilage, bone has a more extensive set of cell types, extracellular specializations for calcification, and the presence of blood vessels, all of which allow for more extensive possibilities for the tissue’s development and remodeling.

Learning Objectives for this unit:

• Understand the variations in structure and function of the three major types of cartilage, with regard to both the cellular and extracellular elements.
• Understand the key ultrastructural features of the chondroblast and how they relate to function.
• Understand the structural features and functions of osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
• Know the major differences in structure and function between woven and lamellar bone, and between compact and cancellous bone.
• Understand the structure and composition of an osteon and how it is formed.

Let's take a look at some tissues.