Connective tissue is classified by cellular patterns and the composition of the matrix. There are 4 categories of connective tissue in adults:
- Connective tissue proper - The matrix is composed of collagen, elastin, and reticulin fibers as well as adipose and mast cells.
- Cartilage - The matrix is composed of firm, gel-like matrix is made up of water, collagen fibers and chondrocytes.
- Osseous tissue (bone) - Bone is comprised of a rigid, mineralized matrix of collagen fibers and osteocytes.
- Vascular tissue (blood) - The matrix is a liquid called plasma, which consists of red and white blood cells, leukocytes, and platelets.