Cartilage and bone are specialized connective tissues which provide the body with mechanical support and protection. They both have many characteristics in common, for example, long bones, such as the femur and humerus, develop from a cartilaginous tissue during the embryonic stage, thus both sharing the same matrix. Like all connective tissues, cartilage and bones are composed of cells, fibers, and amorphous ground substance. Also, mature gross bones in adults have a cartilage component on their articular surfaces.
General Characteristics
Cartilage is composed of three types of cells (fibroblasts, chondroblasts, and chondrocytes), fibers (collagen and elastin), and amorphous ground substance (chondroitin sulfate and hyaluronate). Cartilage is devoid of blood vessels and nerves and it is dominated by non-cellular elements. Thus, their cells must get their oxygen and nutrients by long-range diffusion. This fact is one of the few things that make it different from the bone tissue, which has abundant arterioles and capillaries.
A basic similarity between bone and cartilage is that they both contain living cells embedded in an extracellular matrix reinforced by collagen fibrils. However, bone matrix is heavily calcified, making bone harder and less supple than cartilage. Other common characteristic is that most adult bones existed as cartilaginous models during fetal life. Finally, both bone osteocytes and cartilage chondrocytes are derived from the mesenchyme, which is the embryonic connective tissue in multicellular animals and human beings.
Function
Cartilage and bone are the main mechanical support of the body. They provide a rigid structure for muscle attachment as bones constitute a system of levers upon which skeletal muscles contract to make movement and locomotion possible. Cartilage adds flexible support to this rigid structure.
Below, image of a human long bone (tibia).
