2. HEALING
• Healing is the body’s response to injury in an attempt
to restore normal structure and function.
• Tissue Repair sometimes called healing, refers to the
restoration of tissue architecture and function after
an injury.
3. The process of healing involves 2 distinct processes:
A. REGENERATION
B. REPAIR
4.
5.
6. REGENERATION
Some parenchymal cells are short lived while others
have long lifespan. In order to maintain proper
structure of tissues these cells are under the constant
regulatory control of their cell cycle. These include
growth factor
7. • All the cells divided into 3 groups :
1. Labile cells : The cells continue to multiply throughout life under
normal physiological condition.
2. Stable cell: These cells decrease their ability to proliferate but retain
the capacity to multiply in response to stimuli throughout the adult life.
3. Permanent cells : These cells lose their ability to proliferate around
the time of birth.
8.
9. So regeneration of any type of parenchymal cells involve the following 2
processes :
1. Proliferation of original cells from the margin of injury with
migration so as to cover the gap.
2. Proliferation of migrated cells with differentiation and maturation so
as to reconstitute the original tissue.
10. REPAIR
• It is a healing outcome in which tissues do not return to their normal
architecture and function
• Repair typically results in the formation of scar tissues
• Two process involved in repair :
1. Granulation tissue formation.
2. Contraction of wounds.
11. STEPS IN REPAIR
1. Angiogenesis: It is formation of new blood vessels, which supply
nutrients and oxygen needed to support the repair process
2. Formation of granulation tissue: Migration and proliferation of
fibroblasts and deposition of loose connective tissue, together with the
vessels and interspersed leukocytes, form granulation tissue.
3. Remodeling of connective tissue: Maturation and reorganization of the
connective tissue produce the stable fibrous scar
12.
13. HEALING BY FIRST INTENTION STEPS
• 1 st 24 hours –
• Wounding causes the rapid activation of coagulation pathways, which
results in the formation of a blood clot on the wound surface.
• Neutrophils are seen at the incision margin. They release proteolytic
enzymes that begin to clear the debris.
• Epithelial cell proliferation starts at the edge of the wound.
14. • 3-7 days –
• Neutrophils have been largely replaced by macrophages
• Collagen fibers and fibroblasts are now evident at the incision
margins.
• Epithelial cell proliferation continues forming a covering approaching
the normal thickness of the epidermis.
15. • Weeks –
• The epidermis recovers its normal thickness
• The process of “blanching” begins.
• By the end of the first month: The dermal appendages
destroyed in the line of the incision are permanently lost.
16. THE SEQUENCE OF EVENTS IN SECONDARY
UNION IS
I. Initial hemorrhage: immediately after injury, the space between the
approximated surfaces of incised wound is filled with blood.
II. Inflammatory phase: there is an initial acute inflammatory response
followed by appearance of macrophages.
III. Epithelial changes: the basal cells of epidermis from both the cut
margins start proliferating and migrating towards incisional space in
the form of epithelial action.
17. IV. Granulation tissue: granulation tissue is formed by proliferation of
fibroblasts and neovascularization.
V. Wound contraction: contraction of wound is an important feature of
secondary healing, not seen in primary healing.
VI. Presence of infection: bacterial contamination of an open wound
delays the process of healing.
18.
19. STAGES OF WOUND HEALING
1. Stage of inflammation.
2. Stage of granulation tissue formation.
3. Stage of epithelialization.
4. Stage of scar formation.
5. Stage of maturation.
20. PHASES OF WOUND HEALING
For soft tissue wound healing:
1. Inflammatory phase: It can be broken down into further
a) Clot formation
b) Early inflammation
c) Late inflammation
2.Proliferative phase
3.Maturation phase
22. LOCAL FACTORS:
i. Infection
ii. Necrotic tissue & foreign
body
iii. Poor blood supply
iv. Venous or lymph stasis
v. Tissue tension
vi. Hematoma
vii. Large defect
viii. Recurrent trauma
ix. X-ray radiated area
x. Site of wound
xi. Underlying diseases
23. GENERAL FACTORS
i. Age, Obesity, Smoking
ii. Malnutrition
iii. Vitamin deficiency
iv. Anemia
v. Malignancy
vi. Jaundice
vii. Diabetes
viii. Immunosuppressive
diseases
ix. Steroids and cytotoxic drugs
