Healing or Repair

Repair comprises the replacement of dead or damaged cell by healthy cell / These new cells may be derived deom either the parenchyma or the connective tissue stroma of the injured tissue . The word healing on the other hand has slight6 broader range of application . it includes the resolution also ….

 Three types of healing are described …..

i)                    Healing b y resolution 

ii)                  Healing by regeneration

iii)                Healing by connective tissue repair .

I ..  Healing by resolution – The ideal example is lung in pneumonia . In pneumonia , there is collection of inflammatory exudates in the lumina of alveoli with no damage to the alveolar wall . The exudates is liquefied and scavenged . The alveolus becomes aerated and looks normal. Main phenomenon here scavenging out of exudates .

II .  Healing by regeneration  - Parenchymal regeneration can completely reconstitute the defect leaving no residual trace for prior injury . Example – Regeneration of liver parenchymal cells after uncomplicated viral hepatitis .

III . Repair by connective tissue -  It involves replacement of specialized functionin g cells by non-functioning connective tissue namely mature fibrous tissue . such repair may fill defects and more or less restore morphologic continuity bit it takes the form of connective tissue scarring .