Connective tissue is a good example of a well-structured association of diverse cell types. These cells together form an environment to stay at and to exert their special functions. The functions may be generally combined into a single objective, namely supporting activities that are specific for other cells of the multicellular body.

In loose connective tissue one can encounter fibroblasts #1, #2, macrophages, and mast cells. The cells are surrounded by an extracellular matrix, which includes various fibers and the ground substance.

Connective tissue elements also include cells that form the vascular walls. Endothelial cells line the capillaries. The second layer in the wall of a capillary contains pericytes. In the lumen of microvessels, one may find here some blood cells, namely red blood cells, a white blood cell and platelets.