Cartilage is also a connective tissue derived from mesoderm.
Cartilage is a strong, yet flexible substance, somewhat like hard rubber or like the type of plastic used to make tubing. Cartilage cells, called chondroblasts, make cartilage. Once the chondroblasts have laid down their cartilage, they mature into chondrocytes and take on the responsibility of nourishing and maintaining the cartilage surrounding them. In the embryo, most of the skeleton is first made of cartilage. As the embryo grows, the cartilage is gradually replaced by bone.