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- 您请求的操作仅限于组中的用户:===增殖期===这一阶段在受伤后24-48小时开始,持续2-3周,直到大部分疤痕组织形成。 ====纤维增生和肉芽组织形成==== *增殖期的中心事件。*发生在受伤后3-5天,与之前的炎症期重叠。肉芽组织包括炎症细胞、成纤维细胞和纤维连接蛋白、胶原蛋白、糖胺聚糖和蛋白聚糖基质中的新生血管。< ref name = >“p1”起到了推动作用。西蒙,体育。皮肤伤口愈合。可访问:https://emedicine.medscape.com/article/884594-overview(访问日期:28/02/2019)。 ====上皮化====在脱落的表面形成上皮。这个过程在组织损伤后的几个小时内开始。*涉及伤口边缘的细胞从切口一侧向另一侧迁移,距离小于1mm。伤口在受伤后24-48小时内上皮化。这一上皮层在潜在的伤口和环境之间提供了一个密封。 * Epidermal cells at the wound edges undergo structural changes, allowing them to detach from their connections to other epidermal cells and to their basement membrane. Intracellular actin microfilaments are formed, allowing the epidermal cells to creep across the wound surface. * Occlusive and semiocclusive dressings applied in the first 48 hours after injury may maintain tissue humidity and optimize epithelialization. * When epithelialization is complete, the epidermal cell assumes its original form, ==== Fibroplasia ==== Fibroplasia begins 3-5 days after injury and may last as long as 14 days. * Skin fibroblasts and mesenchymal cells differentiate to perform migratory and contractile capabilities. * Fibroblasts are responsible for the production of collagen, elastin, fibronectin, glycosaminoglycans, and proteases. * Fibroblasts fill the defect left by an open wound as the number of inflammation cells decrease. * As granulation tissue matures, the fibroblasts produce less type III collagen and become more spindly in appearance. They begin to produce the much stronger type I collagen ==== Angiogenesis ==== Angiogenesis results in greater blood flow to the wound and, consequently, increased perfusion of healing factors. Angiogenesis ceases as the demand for new blood vessels ceases. New blood vessels that become unnecessary disappear by apoptosis. * A rich blood supply is vital to sustaining newly formed tissue (as is appreciated in the erythema of a newly formed scar). * The macrophage is essential to the stimulation of angiogenesis and produces macrophage-derived angiogenic factor in response to low tissue oxygenation. [[File:Scars from skin flap.jpg|right|frameless]] ==== Contraction ==== * Contraction results in a decrease in wound size eg a 2-cm incision may measure 1.8cm after contraction. * Loose tissues contract more than tissues with poor laxity, and square wounds tend to contract more than circular wounds. * Wound contraction depends on the myofibroblast located at the periphery of the wound, its connection to components of the extracellular matrix, and myofibroblast proliferation. * Radiation and drugs, which inhibit cell division, have been noted to delay wound contraction.