This connective tissue is flexible, well vascularized, and has little tensile strength. It appears as a loose, irregular network of fibers and cells with abundant ground substance . The ground substance is not preserved in routine histological preparation, resulting in an empty appearance with scattered cells in section. Dense connective tissue has relatively abundant collagen fibers , less ground substance, and even fewer cells, mostly fibroblasts. Dense connective tissue can be sub-classified into regular and irregular types.
Adipose tissue has an especially high content of fat cells in loose connective tissue.
Macrophages anchor to this framework. It is marked by very abundant ground substance, giving a jelly-like consistency. The loose structure provides a pathway for cells to migrate and proliferate during morphogenesis. The chief function is to produce the cells of blood and lymph. This tissue is a complex mixture of different cell types and a rich lattice of reticular fibers.