Inflammation provides the trigger for tissue repair . There are two processes involved in the repair : regeneration and healing .

The difference between the two types of repair is the cell type that will make the replacement . In regeneration there is a replacement for the morphofunctional cells while in healing is the replacement by fibrous tissue.

The entire repair process is controlled by growth factors that are stored in the extracellular matrix (ECM ) . Furthermore , the process of repair needs cell proliferation , angiogenesis and extracellular matrix deposition. The ECM is extremely important in the healing process because it supports cell adhesion , it is the reservoir of growth factors and, in particular , is composed of fibroblasts that synthesize collagen which is essential in healing .

There are basically three cell types related to tissue repair : labile , stable or quiescent cells and permanent cells . These cells are in different stages of the cell cycle. Stable cells are in G0 , ie, they are at rest and when they receive appropriate signals, they enter into the cell cycle. They are little specialized cells such as epithelial cells . Some cells have cell cycle shortened . It is the case of labile cells which are induced to divide more rapidly . The permanent cells are highly specialized ones such as neuronal cells and cardiomyocytes. We can make the analogy that the more specialized a cell is , the less it proliferates . Thus , only permanet cells are related to healing because, in that case, the dead cells are replaced by fibrous tissue .

Regeneration

The inflammatory process will bring new blood vessels and ECM . Growth factors present in the ECM will induce the labile and stable cells to enter into a shorter cell cycle in order to replace by the parenchymal cells of the same organ cells .

Healing

Having the final components of inflammation available , the body will use angiogenesis and fibroblasts to healing. In the affected area will be a deposit of fibroblasts ( fibroplasia ) that synthesize collagen . Then there is the remodeling where the synthesized collagen will acquire resistance to the scar .

Healing can be further classified into first and second intention . The first intention occurs when the lesion is not extensive and without secondary infection, while the second intention occurs when the lesion is very extensive , reaching the stroma and the wound is contaminated .

It is important to know that what will drive the type of repair that will occur will be :
1 - the type of tissue reached
2 - the type of injury
3 - the extent of injury

As in all processes of our body , there are factors that influence the healing process . These are called local and systemic factors . As local factors we can cite foreign bodies , lesion size and location of the injury , for example. As systemic factors we can cite nutrition, circulatory status and metabolic state , for example.