Porth's Essentials of Pathophysiology, 4e

issue repair, which overlaps the inflammatory pro- cess that was discussed in Chapter 3, refers to the restoration of tissue structure and function after an injury. Tissue repair can take the form of regeneration, in which injured cells are replaced with cells of the same type, sometimes leaving no residual trace of previous injury; or it can take the form of replacement by con- nective (fibrous) tissue, which leads to scar formation or fibrosis in organs such as the liver or lung. For many types of common injuries, both regeneration and con- nective tissue replacement contribute to tissue repair. This chapter is divided into two parts. The first part dis- cusses cell proliferation and regeneration, the cell cycle, the role of stem cells, growth factors, and the extracel- lular matrix in tissue renewal. The second focuses on connective tissue repair, cutaneous wound healing, fac- tors that affect wound healing, and the effect of aging on wound healing. Cell Proliferation and Tissue Regeneration and Repair 4 C h a p t e r Cell Proliferation andTissue Regeneration Tissue repair involves the proliferation of various cells, and close interactions between cells and the extracel- lular matrix (ECM). Body organs and tissues are com- posed of two types of tissues: parenchymal and stromal. The parenchymal tissues consist of the functioning cells of an organ or body part: whereas, the stromal tissues contain the supporting connective tissues, blood vessels, fibroblasts, nerve fibers, and extracellular matrix. T

Cell Proliferation and Tissue Regeneration Cell Proliferation Versus Differentiation The Cell Cycle Proliferative Capacity of Tissues Stem Cells Influence of Growth Factors Extracellular Matrix and Cell–Matrix Interactions Healing by Connective Tissue Repair Phases of Repair Angiogenesis and Ingrowth of Granulation Tissue Emigration of Fibroblasts and Deposition of Extracellular Matrix Maturation and Remodeling of the Fibrous Tissue Cutaneous Wound Healing Healing by Primary and Secondary Intention Phases of Healing Factors That Affect Wound Healing Nutritional Status Blood Flow and Oxygen Delivery Impaired Inflammatory and Immune Responses Infection, Wound Separation, and Foreign Bodies Wound Healing in the Elderly

Cell Proliferation Versus Differentiation

Cell proliferation refers to the process of increasing cell numbers by mitotic division. Cell differentiation is the process whereby a cell becomes more specialized in

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