Tenoblasts are immature tendon cells. They are spindle-shaped and have numerous cytoplasmic organelles, reflecting their high metabolic activity. As they mature, the tenoblasts lengthen and transform into tenocytes.

Tenocytes have a lower nucleus / cytoplasm ratio than tenoblasts, with decreased metabolic activity.

The remaining 5% to 10% of the tendon cell elements are chondrocytes at the sites of bone insertion and fixation, synovial tendon cells and vascular cells, including capillary endothelial cells and smooth muscle cells. the arterioles.

The fundamental substance of the extracellular matrix network surrounding the collagen and tenocytes is composed of proteoglycans, (GAGs), glycoproteins and several other small molecules.

Proteoglycans are strongly hydrophilic, which allows the rapid diffusion of water soluble molecules and the migration of cells.

Adhesive glycoproteins, such as fibronectin and thrombospondin, participate in the repair and regeneration processes of the tendon.

Tenascin-C, is another important component of the extracellular matrix network of the tendon, is abundant
in the body of the tendon and in the osteotendinous and myotendinous junctions.

Tenascin-C, contains a series of repetition of the domains of fibronectin type III and can function as an elastic protein.

The expression of Tenascin-C, is regulated by mechanical stress, can also play a role in the alignment and orientation of the collagen fiber.