Scabs indicate which phase of wound healing lag

Healthy granulation tissue is dependent upon the fibroblast receiving sufficient levels of oxygen and nutrients supplied by the blood vessels. The colour and condition of the granulation tissue is often an indicator of how the wound is healing. Maturation is the final phase and occurs once the wound has closed. This phase involves remodelling of collagen from type III to type I. Place referral orders on your computer or mobile device and track order status for all your orders in real time.

But how, exactly, does our body heal? The cascade of healing is divided into these four overlapping phases: Hemostasis, Inflammatory, Proliferative, and Maturation. Hemostasis, the first phase of healing, begins at the onset of injury, and the objective is to stop the bleeding. In this phase, the body activates its emergency repair system, the blood clotting system, and forms a dam to block the drainage.

During this process, platelets come into contact with collagen, resulting in activation and aggregation. An enzyme called thrombin is at the center, and it initiates the formation of a fibrin mesh, which strengthens the platelet clumps into a stable clot.

The 4 phases of wound healing. Healing begins with Hemostasis. During Phase 2, a type of white blood cells called neutrophils enter the wound to destroy bacteria and remove debris. These cells often reach their peak population between 24 and 48 hours after injury, reducing greatly in number after three days. As the white blood cells leave, specialized cells called macrophages arrive to continue clearing debris. These cells also secrete growth factors and proteins that attract immune system cells to the wound to facilitate tissue repair.

This phase often lasts four to six days and is often associated with edema, erythema reddening of the skin , heat and pain. Once the wound is cleaned out, the wound enters Phase 3, the Proliferative Phase, where the focus is to fill and cover the wound.

The Proliferative phase features three distinct stages: 1 filling the wound; 2 contraction of the wound margins; and 3 covering the wound epithelialization. During the first stage, shiny, deep red granulation tissue fills the wound bed with connective tissue, and new blood vessels are formed. During contraction, the wound margins contract and pull toward the center of the wound. In the third stage, epithelial cells arise from the wound bed or margins and begin to migrate across the wound bed in leapfrog fashion until the wound is covered with epithelium.

The Proliferative phase often lasts anywhere from four to 24 days. During the Maturation phase, the new tissue slowly gains strength and flexibility. The Maturation phase varies greatly from wound to wound, often lasting anywhere from 21 days to two years.

The healing process is remarkable and complex, and it is also susceptible to interruption due to local and systemic factors, including moisture, infection, and maceration local ; and age, nutritional status, body type systemic. As vasoconstriction occurs, platelets are released and fibrin leaks from injured vessels. Platelets go through a process of platelet aggregation and with fibrin form a clot that adheres to injured vessels. The end result of this phase is clot formation and the cessation of bleeding.

As discussed before, all phases of wound healing overlap. Platelets will then release growth factors, such as platelet-derived growth factors, and key cytokines that will be participants in upcoming phases of healing. The inflammatory phase is the second phase in the healing cascade and since the phases overlap, it initiates with injury.

The inflammatory phase lasts days and is characterized by the presence erythema, warmth, edema and pain. Neutrophils are one of the major cells involved as they secrete chemicals to kill bacteria and are later replaced by macrophages that will assist in engulfing and digesting bacteria and any other cellular debris.

The best way for me to describe this process would be to refer to macrophages as a bunch Pac-Mans eating all the debris and cleaning everything out. Macrophages produce chemoattractants and growth factors, which are needed for tissue repair.

Macrophages are critical in the repair process as they play a part in releasing growth factors that increases the level of fibroblasts, all essential for the following phase. The proliferative phase is the third phase in the healing process and lasts days.

This phase is characterized by the presence of granulation tissue and ultimately epithelialization. Fibroblasts are a key cell in this phase. Fibroblasts are responsible and lay the foundation for new extracellular matrix ECM for collagen and granulation tissue. In this phase, we go through proliferation, growth of new tissue, angiogenesis, collagen deposition, granular tissue formation, wound contracture and epithelial cell migration.

Granulation tissue consists of macrophages, fibroblasts, immature collagen and blood vessels. Angiogenesis is the formation of new vessels that developed within the granular tissue in order to supply it with blood and nutrients. As granulation tissue develops, fibroblasts stimulate the production of collagen, which gives tissue strength and structure. Once the deficit has been filled with granulation tissue, the wound edges or margins will begin to contract until the wound bed is covered with new epithelium and resulting in the presence of a scar.

Remodeling or also known as maturation phase is the fourth and final phase in wound healing and lasts from 21 days up to 2 years. In this final and longest phase, collagen synthesis is ongoing in order to strengthen the tissue. Remodeling occurs as wound continues to contract and fibers are being reorganized. Wound healing occurs by primary, secondary or tertiary intention. Wounds that heal through primary intention, such as a surgical wounds, refers to the skin being approximated with use of staples, sutures or surgical glue.

These type of wounds heal faster, have a lower infection risk, have minimal tissue loss and heal with minimal scarring. Wounds left to heal by secondary intention, meaning, through granular tissue formation, wound contracture and epithelial cell migration, tend to be more of chronic etiology and because of the delay in healing, are at a greater risk for infection.