Stages of wound healing

The body is a remarkably complex machine, and the process of wound healing is a dynamic example of how our body replaces and repair devitalized cells. But the question is, how does our body heal? We discuss all detailed Stages of wound healing

When the skin is wounded, our body starts an automatic series of events called “cascade of healing” to repair the tissues. This mechanism is based upon the below mentioned four phases:

The Hemostatic phase: 

It is the first phase of healing which begins immediately after the onset of injury to stop the bleeding. The emergency repair system is activated in this phase, i.e., the blood clotting mechanism, which forms a scab, blocking the drainage. During this process, the platelets (thrombocytes) interact with collagen, activating the aggregation. The enzyme called “thrombin” is involved in this mechanism, initiating the formation of a “Fibrin mesh”, which gives strength to platelet clumps, transforming that into a clot.

The Hemostatic phase:

Inflammatory/Defensive Phase: 

This phase focuses on removing debris, destroying the infectious micro-organisms, preparing the wound bed essentially for new tissue growth.

During this phase, neutrophils (a type of white blood cell) enter the wounded site to destroy bacteria and wipe away the debris. These cells reach their peak population between 1 to two days after injury, reducing in number after three days. When the white blood cells leave, macrophages (specialized cells) arrive to continue clearing the debris. These cells also secrete proteins and growth factors that attract the immune cells toward the wound to facilitate tissue repair. This phase lasts for about six days and is associated with erythema (reddening of the skin), edema (swelling due to trapped fluid), pain and heat.

Inflammatory

Proliferative phase: 

When the wound is cleaned out, it enters the proliferation phase, focusing on covering and filling the wound. The proliferation phase consists of three stages:

1-Filling of wound

2-Contraction of wound margins

3-Epithelialization (Covering the wound).

During the wound filling, the deep red granulated tissue fills the wound bed with fibrous connective tissue and new blood vessels. During contraction, the margins of the wound contract and moves toward the centre of the wound. In the third stage (epithelialization), the epithelial cells arise from the wound bed and margins, beginning to migrate across the wound bed until the wound is covered with epithelium. This proliferation phase lasts from four hours to 24 days.

Proliferative phase

Maturation Phase or Remodeling:

During this phase, the new tissue gradually gains flexibility and strength. Then, the collagen fibres reorganize, the tissue matures and remodels, and an overall elevation in tensile strength occurs. This maturation phase varies from wound to wound, lasting from 21 days to two years.

The healing process is unique and complex, but it is also susceptible to local and systemic interruptions, including infection, moisture, age, nutritional factors, body type and maceration (maceration refers to that wet, soft wrinkly wet skin due to moisture) etc. But with the optimized healing environmental factors, the body works in wondrous ways to heal.

Maturation Phase or Remodeling

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