Tissue Regeneration vs. Repair

To increase wound strength and contract it through the formation of new epithelium and realignment of collagen fibers.

It begins about 21 days after an injury and can continue for a year or more.

Collagen is remodeled from type III to type I, which is important for creating a more organized and stronger collagen structure that mimics native tissue.

<p>They are responsible for the degradation of collagens and other ECM components during the remodeling process.</p> Signup and view all the answers

<p>Strength may recover to 70% to 80% of normal skin by three months; however, healed wound areas remain weaker than uninjured skin.</p> Signup and view all the answers

<p>The two primary processes are regeneration, which restores normal tissues, and scarring, which involves the deposition of fibrous tissues.</p> Signup and view all the answers

<p>Adult stem cells can proliferate and differentiate to restore damaged tissues during the regeneration process.</p> Signup and view all the answers

<p>The healing outcomes are influenced by the proliferative capacity of the damaged tissue, the integrity of the extracellular matrix (ECM), and the chronicity of the associated inflammation.</p> Signup and view all the answers

<p>Labile tissues are continuously dividing and are constantly replaced, while stable tissues are quiescent but can divide after injury.</p> Signup and view all the answers

<p>Fibrosis is the deposition of collagen and other extracellular matrix components that patch tissue, typically occurring when restorative capacity is limited or after severe tissue injury.</p> Signup and view all the answers

<p>Angiogenesis is crucial as it provides essential nutrients and oxygen required for healing by generating new blood vessels.</p> Signup and view all the answers

<p>Chronic inflammation can hinder tissue healing by promoting fibrosis rather than regeneration.</p> Signup and view all the answers

<p>The fibroproliferative response refers to the body's mechanism to deposit collagen and ECM components in response to severe injury, resulting in scar formation.</p> Signup and view all the answers

<p>Examples include cardiomyocytes and most neurons.</p> Signup and view all the answers

<p>They regenerate through proliferation of residual cells and differentiation of tissue stem cells.</p> Signup and view all the answers

<p>The liver can regenerate through proliferation of remaining hepatocytes and repopulation from liver progenitor cells.</p> Signup and view all the answers

<p>Growth factors synthesized by macrophages, epithelial, and stromal cells drive cell proliferation during tissue regeneration.</p> Signup and view all the answers

<p>Repair begins with the formation of a hemostatic plug within minutes of injury.</p> Signup and view all the answers

<p>Macrophages are recruited to the site of injury to play a central role in the repair process.</p> Signup and view all the answers

<p>Tissue regeneration is usually limited, with some capacity in organs like the pancreas and lung.</p> Signup and view all the answers

<p>Granulation tissue becomes apparent by 3 to 5 days after an injury.</p> Signup and view all the answers

<p>Extensive damage leads to incomplete regeneration and scar formation.</p> Signup and view all the answers

<p>Nephrectomy elicits compensatory hypertrophy and hyperplasia of proximal duct cells in the remaining kidney.</p> Signup and view all the answers

<p>Endothelial cell proliferation forms new blood vessels through a process called angiogenesis.</p> Signup and view all the answers

<p>Fibroblasts proliferate and migrate into the injury site, laying down collagen fibers crucial for scar formation.</p> Signup and view all the answers

<p>Granulation tissue matures to consist mainly of dense collagen and inactive fibroblasts, resulting in scar formation.</p> Signup and view all the answers

<p>TGF-β (Transforming Growth Factor Beta) promotes fibroblast migration and proliferation.</p> Signup and view all the answers

<p>Progressive vascular regression leads to an avascular scar, contributing to the scar's stability and strength.</p> Signup and view all the answers

<p>Myofibroblasts are specialized fibroblasts that contribute to scar contraction during healing.</p> Signup and view all the answers

<p>Granulation tissue is characterized by proliferating fibroblasts, delicate capillaries, and inflammatory cells.</p> Signup and view all the answers

<p>Angiogenesis leads to leaky new blood vessels, increasing vascular permeability and causing edema.</p> Signup and view all the answers

<p>Collagen is critical for wound strength and is predominantly produced as healing progresses.</p> Signup and view all the answers

<p>Clinically, granulation tissue appears as pink, soft, and granular beneath a scab.</p> Signup and view all the answers