Wound healing
Inflammation
"Itis"
is the normal response of the body to an insult. A
local process
Clinical
Features
Heat redness swelling pain loss
of function
Mechanism of inflammation
Damaged
tissues release histamine, a powerful vasodilator, from mast cells, leading to
hyperaemia
Increases
the permeability of capillaries leading to the formation
of tissue fluid and swelling
Proteins
from blood found in the tissues; - fibrinogen --- fibrin
This
forms a framework for later repair.
Cells
are supplied with nutrients for repair.
Phagocytes
migrate to the site of injury.
Inflammation
is therefore normal, a necessary first stage in the healing process.
Repair
Initial
and other insulting factors must be removed
Capillaries
sprout new branches into damaged area
Adjacent
fibroblasts divide and produce fibrous tissue
Capillaries
+ fibre making cells = granulation tissue
Adjacent
tissue cell mitosis, inability to produce hair folicles and sweat glands
Stages in wound healing A continuous process but;
Stage I.
Inflammatory stage
0 - 3
days
Includes
haemostasis
Stage 2.
Destructive/migratory
1 - 6
days
Macrophages
engulf and digest infectious agents and dead tissue
Increased
mitosis in fibroblasts
Angioneogenesis
Stage 3.
Proliferation/granulation
3 -24
days
Fibroblasts
form collagen fibrils
Increasing
tensile strength
New
capillary loops are supported in a collagen framework
Signs of
inflammation subside
Wound
remains red and raised
Stage 4.
Maturational
Collagen
fibres start to contract the wound so wound gets smaller
Vascularity
decreases
Epithelium
migrates inward from the wound edges and hair folicle remnants
Migration
can only occur over viable tissue, (moist environment)
Healing
stops with contact inhibition
Types of
healing
Primary
intention - little
tissue loss, little risk of
infection, wound edges well
approximated, healing 7 - 10 days
Secondary
intention - risk of
infection, wound left open to heal
by granulation, tissue loss prevents
approximation, length of process.