Wounds
It is an injury to living tissue caused by a cut, blow or other
impact, in which the skin is broken.
Wound healing
It is a complex and dynamic process that results in the
restoration of anatomic continuity of structure and function.
Components involved in this process are;
Oxygen, nutrition and growth factors in blood.
PHASES OF WOUND HEALING
- Hemostasis and vascular response
- Inflammatory process
- Proliferative or resolution phase
- Maturation or reconstruction phase
Components of blood has vital role in the process of
wound healing ;
Blood has mainly 4 components:
- Plasma
It involves plasma proteins, immunoglobulins, clotting factors,
fobrinogen etc.
2. Red blood cells
3. White blood cells
It involves neutrophils, eosinophils, basophils, lymphocytes and
monocytes.
4. Platelets
Components of blood and
its functions in wound healing are discussed below:
In first phase, that is hemostasis and vascular response.
- There will be vasoconstriction initially after injury.
- Platelets : helps in clot formation and stops
bleeding
- Plasma proteins : Forms fibrous mesh work
around the wound.
- Combination of clot with platelets and mesh work occurs to
minimize bleeding.
- Later vasodilation occurs for the supply of more blood to the
area. Plasma will also be supplied.
- Plasma - phagocytes :they will dilute toxins
and carry oxygen and nutrients
- Due to all these redness and warmness occurs.
In second phase, that is inflammatory phase ;
- This phase is a defense mechanism produced by cells or tissue
against the microorganisms.
- WBC's role : they get activated in
inflammation and infection.
- Neutrophils has the vital role.
- More neutrophils are transported to the wound area.
- Blood vessels are madeup of endothelium and neutrophils reaches
and migrate around the area. It is called marginating.
- Histamine will produce and they dilate the vessels and create
space in between the endothelium in that area.
- Through these spaces, nutrients and all needed factors pass to
the wound area along with neutrophils.
- Transport of neutrophils through endothelial space created is
called diapedesis.
- The process of movement of neutrophils towards the affected
area is called chemotaxis.
- Neutrophils are also known as poly morphonucleus neutrophils.
They are secreted as either mature or immature. The mature ones are
phagocytic.
- Macrophages : phagocytosis, activates in 48
hours after injury,remove blood cells or dying cells through
phagocytosis.
- Eosinophils and basophils: migrate towards the
wounded area. Basophils secrete histamine and eosinophil secrete
antihistamines.
- Mast cells : get activated
if any injury occurs and produces histamine, serotonin,
leukotrines, prostaglandins.
- Kinins, kind of plasma proteins. Bradykinins
reduce pain and increase vascular permeability. Cytokines helps in
growth and development of cells with immunity development.
Third phase, that is proliferative phase,
- Macrophages : it secretes or stimulate certain
factors ;platelet derived growth factors, angiogenitic growth
factors, transforming growth factors.
4th phase, that is maturation phase,
- Formation of scars and its remodelling.
Note :
In this note only the function of blood components are
described. There are many other processes happening in the process
of wound healing.