Cytology and General Histology: Atlas

Connective and supporting tissues

are marked by a high content of intercellular substance where fibers make up a considerable volume (these tissues are also called fibrous tissues)
may have a varied amount of ground (amorphous) substance

Connective tissue proper types (loose and dense tissues) differ by features of intercellular substance arrangement

the intercellular substance is marked by a prevalence of amorphous component with a rather low fiber content
collagen, elastic, and reticular fibers are not ordered in the intercellular substance
the tissue contains interacting cells differing in their functions and origin:
- derivatives of stromal stem cells in the red bone marrow: various types of fibroblasts, adventitial cells, adipose cells
- derivatives of hematopoietic stem cells in the red bone marrow: macrophages, mast cells, granulocytes and agranulocytes, plasma cells
- derivatives of cells from the neural crest: melanocytes
this is the most common type of connective tissues. It constitutes the stroma of many organs (layers between lobules, membranes, and layers); it envelops blood vessels and nerves, composes the skin and mucous membranes

its intercellular substance contains collagen and elastic fibers predominantly; there is little ground substance
the collagen fibers are arranged in bundles that are not ordered. These bundles interlace forming a 3D network
fibroblasts and fibrocytes are the most common cells, macrophages are not so common, as well as mast cells and white blood cells
the tissue is found in the dermis, capsules of parenchymatous organs, perichondrium, and periosteum

its intercellular substance is represented by collagen fiber bundles that are parallel to one another
there are elastic fibers and a little ground substance between the collagen fiber bundles
cells are not abundant, most of them are fibrocytes
this is the main tissue in tendons, ligaments, and aponeuroses