Early phase of scar tissue formation is occurs in which of the following kinds of tissue..? options are, granulation, fibrous, keloid, cicatrix
Answers
Explanation:
The proliferative phase is characterized by the formation of granulation tissue, reepithelialization, and neovascularization. This phase can last several weeks.
Answer:
Scar
Scar tissue mechanics differ somewhat from normal connective tissue mechanics. Normal connective tissue is mature and stable, with limited pliability. Immature scar tissue is much more dynamic and pliable. Scar tissue formation occurs in four distinct phases. Each of these phases shows characteristic differences during phases of immobilization and mobilization.1-3
The first phase of scar tissue formation is the inflammatory phase. This phase occurs immediately after trauma. Blood clotting begins almost instantly and is followed by migration of macrophages and histiocytes to start débriding the area. This phase usually lasts 24 to 48 hours, and immobilization is usually important because of the potential for further damage with movement. Some exceptions to routine immobilization exist. For example, in an anterior cruciate ligament (ACL) reconstruction, in which the graft is safely fixated and damage from gentle movement is unlikely, there may be a great advantage in moving the tissue as early as the first day after surgery. Research indicates that early mobilization leads to more rapid ligament regeneration and ultimate load to failure strength in surgically repaired ACLs.32
The second phase of scar tissue formation is the granulation phase. This phase is characterized by an uncharacteristic increase in the relative vascularity of the tissue. Increased vascularity is essential to ensure proper nutrition to meet the metabolic needs of the healing tissue. The granulation phase varies greatly depending on the type of tissue and the extent of the damage. Generally speaking, the entire process of scar tissue formation is lengthened if the damaged tissue is less vascular in its nontraumatized state. For example, tendons and ligaments require more time for scar tissue formation than muscle or epithelial tissue. Movement is helpful in this phase, although the scar tissue can be easily damaged. The physician and therapist need to work closely to determine the extent of movement relative to the risk.
The third phase of scar tissue formation is the fibroplastic stage. In this stage the number of fibroblasts increases, as does the rate of production of collagen fibers and ground substance. Collagen is laid down at an accelerated rate and binds to itself with weak hydrostatic bonds, making tissue elongation much easier. This stage presents an excellent window of opportunity for the reshaping and molding of scar tissue without great risk of tissue reinjury. This stage lasts 3 to 8 weeks, depending on the histologic makeup and relative vascularity of the damaged tissue. Scar tissue at this phase is less likely to be injured but is still easily remodeled with stresses applied (Fig. 2-9). Additionally, myofibroblasts are the most active in the last two phases of scar tissue maturation. Myofibroblasts are believed to be responsible for the scar tissue shrinkage that occurs in this and the next phase of scar tissue healing.1,3,6-8,37
The final phase of scar tissue formation is the maturation phase. Collagen matures, solidifies, and shrinks during this phase. Maximal stress can be placed on the tissue without risk of tissue failure. Because collagen synthesis is still accelerated, significant remodeling can take place when appropriate mobilizations are performed. Conversely, if they are left unchecked, then the collagen fibers can cross-link and the tissue can shrink significantly. At the end of the maturation phase, tissue remodeling becomes significantly more difficult because the tissue reverts to a more mature, inactive, and nonpliable status.