See below Essay Example | Topics and Well Written Essays - 1000 words

See below - Essay Example The capillaries play an important role in healing a wound. The four overlapping phases are used to explain the healing process. This is a systematic phenomenon. The four phases include homeostasis, inflammation, proliferation, and maturation. Homeostasis is a process which involves the platelets to form clots. Furthermore, the inflammatory cells deride injured tissue during the inflammatory phase. Epithelialization, fibroplasia, and angiogenesis occur during the proliferative phase (Romo III, n.d). The hemorrhage caused by disruption in the blood vessels is controlled by clot formation which contains fibrin mesh with aggregated platelets embedded in it. Fibrin is the end product of coagulation pathway which causes homeostasis to take place. It provides a scaffold for the migration of inflammatory and mesenchymal cells (Wound Healing, n.d). Platelet aggregation leads to release of cytokines. These cytokines influence wound healing either directly or indirectly. The processes of clot f ormation and platelet aggregation halt when stimuli for clot formation fritter away. Lysis of clot starts along with clot formation and is mediated by plasminogen activator. This activator converts plasminogen to plasmin (Wound Healing, n.d). The second phase is called inflammation. It starts when the tissue trauma stimulates the inflammatory response. â€Å"Immediately after injury intense local vasoconstriction occurs, mediated by circulating catecholeamines and prostaglandins released by injured cells. This is followed by vasodilatation and increased capillary permeability resulting in local edema. This is mediated by histamine, kinins, prostaglandins, leukotrienes, and endothelial cell products† (Wound Healing, n.d). The tissue does not observe presence of any leukocytes as yet. The wounded tissues contain neutrophils which hare the first leukocytes to appear in the wounded tissues. They phagocytose damaged tissue or bacteria. Neutrophils themselves are phagocytosed by ma crophages (Wound Healing, n.d). There are a few symptoms observed when the wound is healing because of the physiological changes. The pH change is observed because of the breakdown of tissues and bacteria which also causes pain. This also results in swelling and decreased tissue oxygenation due to disruption of blood vessels (Wound Healing n.d). Furthermore, the white blood cells namely monocytes and lymphocytes start performing their functions in the healing process. Monocytes turn into macrophages when these white blood cells migrate from capillaries into extra vascular space. Macrocytes phagocytose bacteria and tissue debris and secrete enzymes called collagenase and elastase, which are responsible for breaking down damaged matrix (Wound Healing, n.d). Lymphocytes produce various factors like HB-EGF (Heparin binding epidermal growth factor) and basic fibroblast growth factor. Adding on to this, they are also involved in cellular and humoral immunity. Neutrophilis dominate for the initial 24-48 but 48-72 hours later they are outnumbered by macrophages which persist for a few days. However, after 5-7 days fibroblasts are the principal cell type (Wound Healing, n.d). The third phase called proliferation constitutes epithelialization, fibroplasias and angiogenesis. Epithelialization is the â€Å"process of covering a denuded surface with epithelium† (Medical Dictionary, n.d). Fibroplasia is another part of the proliferative phase. It