Areolar tissue is the most common connective tissue in the body.  It is a network of loosely organized collagen, elastic and recticular fibers that are maintained by fibrocytes.  This mesh allows blood vessels, nerve and interstitial fluids to penetrate.  Immune cells (such as leukocytes) could also be found in the network.  Its function is to nourish the overlaying epithelial tissues and holding structures in place.

Areolar tissue could be found almost everywhere in the body.  Notable locations include the underneath of epithelial tissues, lamina propria, intestinal mesentery, and serous membranes.