Types of Tissues
Connective tissue is made up of cells and fibers in a "jelly-like" ground substance. Present throughout the body, connective tissue holds parts together and acts as packing. There are several kinds of connective tissue, which differ in the amount and type of cells and fibers in their makeup. Most common is loose areolar tissue, which contains most of the basic connective tissue components or ground substance: Mast cells, collagen fibers, macrophage cells, fibroblasts, blood supply, fat cells, elastic fibers, reticulin, nerve supply and plasma cells. Widely distributed throughout the body, areolar tissue forms binding sheaths around muscles, nerves and blood vessels, and is present within organs as filling materials. Tendons, a dense connective tissue which attaches muscle to bone, are bundles of inelastic collagen fibers (1) made by fibroblasts (2) in the ground substance. Adipose tissue, another connective tissue of the body, is composed mostly of fat cells. It cushions internal organs, forms an insulating layer under the skin and provides a fuel store. Cartilage is also a connective tissue found in the body, but differs from other connective tissue because it has no blood vessels.