department of Pathology
2
nd
class /2021-2022
Prof. Dr.Nihad N. Hilal
Repair of damaged tissues occurs by two
types of reactions :
-
regeneration by proliferation of residual
(uninjured )cells and maturation of tissue
stem cells,
-
and the deposition of connective tissue to
form a scar.
Types of healing
Healing by first intention
0 hr:
incision filled with clot
3-24 hr:
neutrophils from the margins infiltrate the clot.
Mitosis in basal epith ; epith closure by 24-48 hrs
Day 3:
neutrophils replaced by macrophages.
Granulation tissue begins to appear.
Day 5:
incision filled with granulation tissue.
Wk 2:
proliferation of fibroblasts + collagen deposition;
inflam & new blood vessels disappeared
Month 2:
scar consists of connective tissue covered by
epidermis
Factors affecting inflammatory-reparative response
1. Adequacy of blood supply
2. Nutritional status (protein ,vitamin C)
3. presence/ absence of infection
4. presence/ absence of diabetes mellitus
5.steroid therapy
Keloid scar 1
2.Keloid scar
Thank you