The body consists of cells and extracellular matrix (ECM). The ECM is composed of two parts, a fibrous part and a fluid part called ground substance.
Cells in the fascia produce, control and maintain all the ingredients of the ECM.
- Fibroblasts – produce collagen, elastin, carbohydrates, signal proteins, collagenase, etc, depending of mechanical signals of pressure and vibration. Fibroblasts build up, break down and maintain the ECM.
- Fasciacytes – produce hyaluronan for the ground substance. Found near the sliding layers between the different fascial layers and in the endomysium.
- Myofibroblasts – Fibroblasts can morph into myofibroblasts, cells which have a contracting ability. This ability helps to close wounds. They also help heal injuries by producing cytokines, which enhance the inflammatory response.
- Immune Cells – T cells, mast cells, macrophages, lymphocytes, etc.
- Telocytes – a new cell discovered in fascia. Mechano-sensitive cells vital to many physiological processes. Seems to be major player in communication between cells.
- Adipocytes – also lipocytes or fat cells. Energy storage and they also have important endocrine functions (produce hormones).
- Collagen – The most abundant protein in the body. Type I and III are the types mainly found in fascia and they form fibers to resist tension and adapt to mechanical stress. Collagen gives tensile strength and structure to the tissue.
- Elastin – Gives resilience and elasticity to the tissue. Found in elastic cartilage, loose fascia, skin, lungs, vascular walls, but also in small amounts in tendons and ligaments to give the property to recoil.
- Reticulin – Formed of collagen III fibers. Forms the collagen network around the organs and in the covering around muscle fibers, endomysium.
Ground substance (he fluid part of fascia)
- Glucosaminoglycans – GAGs – long polysaccharides. Large organic molecules that trap water. Together with the strength of collagen it gives the ECM the property to resist compressive forces. Include hyaluronan, chondroitin sulfate, dermatan sulfate, heparan sulfate, heparin and keratan sulfate
- Proteoglycans – PGs – occur when GAGs are bound to a protein chain. Peptides that bind water, add cushioning properties.
- Hyaluronan – HA – Hyaluronan (hyaluronic acid, but not an acid).
- Link proteins – connect to molecules in the ECM.
- Collagenase – An enzyme that breaks down collagen. Produced from fibroblasts when needed.
- Integrins – Link proteins in the cell membrane that facilitate the adhesion of molecules in the ECM to to the cell. Mediate cell to cell and ECM to cell interactions. Activate signal transduction from the ECM via the cytoskeleton to the nucleus.
- Growth Factors – Signaling molecules between cells, for example cytokines and hormones. Stimulate and regulate cell function, like rate of cell growth and proliferation. They bind to specific cell receptors on the surface of the target cell.