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wound healing
pathology
Question | Answer |
---|---|
wound healing begins with this | cell or tissue loss |
describe two categories that tissue loss can be a result of | it can be natural (regeneration/renewal), or due to an injury (repair) |
describe two responses to tissue loss | cell proliferation and migration, scaffolding (deposition and reorganization/remodeling of the ECM components) |
describe natural loss of cells/tissue | sloughed epithelia (skin, mucosa). there must be a balance of proliferation and apoptosis, senescence, or mechanical loss |
describe a pathologic process | injury/inflammation/destruction. loss of prenchymal cells, loss of stromal cells and tissue (CT, blood vessels, nerves) that support function (fibroblasts) |
during cell/tissue renewal or repair from minor injury, this type of cell proliferates | parenchymal cell |
during cell/tissue renewal or repair from more extensive injury, this type of cell proliferates | stromal cell |
during healing after an injury, this process disrupts the basic architecture of the entire region of the cell | fibrosis |
name the cellular components of repair | inflammatory ells, parenchymal cells (restore function), fibroblasts and other stromal cells (repair tissue), endothelial cells |
this type of tissue has continuously dividing cells, and have a constant cell loss. ex: surface epithelium; blood cell progenitors | labile |
this type of tissue has quiescent cells. they are primarily in Go phase and have limited ability ot proliferate, and can be stimulated to enter the G1 cell cycle. found in parenchyma and stroma of most solid organs ex: fibroblasts, endothelial cells | stabile |
this type of tissue hasmostly post mitotic cells. they don't engage in mitosis normally and there is not a lot you can do to stimulate mitosis. ex: cardiac myocytes, neurons | permanent |
name the sequence of wound healing | hemostasis, inflammation, provisional matrix, granulation tissue, fibroblast proliferation and collagen deposition/remodeling, re-epithelialization, wound contraction, increase in wound tensile strength |
in a provisional matrix, there is a temporary ECM and this type of collagen is present | type III |
during increased wound tensile strenngth, this type of collagen is present during mature scar formation | type I |
describe the three phases of wound healing | inflammation (clot formation and chemotaxis), proliferation (re-epithelialization, angiogenesis, and granulation tissue, provisional matrix), maturation (collagen matrix, wound contraction |
name three conditions affecting repair | location, amount and nature of ECM at site of injury, blood supply |
name several additional factors affecting tissue repair | nutritional status, metabolic status, circulation, hormones, infection, mechanical forces, foreign bodies, size, location, type of wound |
when differentiating between primary and secondary intention, this is an important factor in healing | presence of stem cells, depth of skin, adequate capacity of wound contraction |
during repair of liver tissue, these two factors result because of impaired blood flow | portal hypertension and cholestatic jaundice: because of disruption of blood flow an dmovement of bile through the hepatic lobules |
what happens in cardiac healing | loss of cardiac myocytes results in fibrosis bc cells are post mitotic and do not proliferate, patchy loss of cells, (ischemic heart disease/cardiomyopathy), diffuse loss of cells: MI, coagulative necrosis, granualtion tissue and immature scar. |
what happens during differential healing of hte nervous system? | neurons are also post mitotic and lack reliable capacity ot proliferate, there is axonal regeneration following trauma: axons in PNS can regenerate and remake synapses, axons in CNS cannot, scarrin ghappens via glial cell proliferation |
list three problems with excessive wound healing | excessive scar formation (hypertrophic scar), keloid, wound contracture |
excessive scare formation | hypertrophic scar |
exuberant, disorganized collagen deposition within dermis that extends beyond anatomic confines of normal structure | keloid |
deformity of wounded tissue and surrounding structures. in somatic body, it happens on palms, soles where skin is relatively close to tendons and they become caught in contracting wound. in visceral body, it can happen in the bowl and cause bowel obstruct | wound contraction |
exuberant overgrowth of granulation tissue: happens in gingiva of pregnant women | pygenic granuloma |
granulation tisse extends above the epithelial surface and precludes re-epithelialization | proud flesh (vet medicine) |
excessive, presistent fibrosis following injury or surgical incisions within soft tissues | desmoids (aggressive fibromatosis) |