A vital trait of living organisms is their capacity for self-repair. Whether an injury is surgical or accidental it will generate an attempt, by the host, to restore tissue continuity. Two processes are involved in healing: repair and regeneration. Repair is a “stop-gap” reaction designed to reestablish the continuity of interrupted tissues with undifferentiated scar tissue. Regeneration entails the replacement of damaged tissue with cells of the type lost and is possible only in tissues with a sustained population of cells capable of mitosis.