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Pathology Exam 1 > Repair of Cell Injury > Flashcards

Flashcards in Repair of Cell Injury Deck (92)
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What is the definition of healing?

A response to tissue injury, and represents an attempt by the organism to restore integrity to an injured tissue

  • overlaps the inflammatory process
  • induction of an acute inflamm response


What happens if the injury results in destruction of epithelium ONLY?

This is an erosion; heals exclusively by regeneration of parenchymal cells


What happens if the injury results in destruction of the basement membrane (extracellular matrix)?

A scar will form ("healing")


What 2 processes does repair occur by?

  1. Complete regeneration: replacement of dead cells (tissue) by proliferation of parenchymal cells of same type (return to normal state)
  2. Incomplete regeneration/healing: replacement by connective (fibrous) tissue -> permanent scar formation


What are the 3 groups of cells of regenerative capacity?

  1. Labile cell - constantly proliferating
  2. Stable cell - quiescent, minimal replicative activity
  3. Permanent cell - terminally differentiated, nonproliferative


What cells constitute the labile cells?

Epithelium of skin, respiratory tract, GI tract, urinary tract, lymphoid cell, bone marrow, vagina, cervix, bladder


What cells constitute the stable cells?

Parenchymal cells in liver, alveolar cells of lung, epithelium of kidney, pancreas, salivary gland


What cells constitute the permanent cells?

Myocardium, skeletal muscle, neuron


What are the cell cycle phases?

  • G1 phase = presynthetic
  • S phase = DNA synthesis
  • G2 phase = premitotic
  • M phase = mitotis
  • G0 phase = nonproliferative (growth arrest)


At what phase can cells leave the cell cycle and then either cease proliferation, differentiate, or eventually be recruited back to the cycle?

G1 phase


At what phase are the continuously cycling labile cells?

S phase

  • remain in the cell cycle at all times
  • can easily regenerate after injury
  • contain a pool of stem cells


At what phase are the quiescent, stable cells?

G0 but can be recruited back into G1


At what phase are the permanent cells?


  • cells cannot undergo mitotic division
  • cells stop multiplication early in neonatal life


Fill in chart

  1. Complete regeneration
  2. Fibrous repair
  3. Complete regeneration
  4. Fibrous repair
  5. Fibrous repair
  6. Fibrous repair


What regulates the mechanisms involved in repair?

  1. Growth factors
  2. Extracellular matrix synthesis and collagenization
  3. Cell-to-cell and cell-to-matrix interactions


What proteins stimulate the survival and proliferation of particular cells by binding to a specific receptor on the target cell?

Growth factors


Which growth factor is a polypeptide present in saliva, milk, urine, plasma, and macrophages?

Epidermal Growth Factor (EGF)


What function does EGF have?

Mitogenic for a variety of epithelial cells:

  • Acts on keratinocytes -> migrate/divide
  • Acts on fibroblasts -> produce "granulation" tissue, synthesize ECM/collagen


Which growth factor is primarily found in the alpha granules of platelets and is released subsequent to platelet activation?

Platelet-derived Growth Factor (PDGF)

  • Also produced by activated macrophages, endothelium, and smooth muscles


What functions do PDGF have?

  • Causes proliferation/migration of fibroblasts, smooth muscle cells, and monocytes
  • Chemotactic for MANY cells
  • Another KEY player in formation of granulation tissue


Which growth factor stimulates fibroblast proliferation and angiogenesis (neovascularization)?

Fibroblast Growth Factor (FGF)


What does neovascularization involve?

Enzymatic degradation of the basement membrane of the parent vessel -> migration of endothelial cells toward the angiogenic stimulus -> proliferation of endothelial cells -> maturation of endothelial cells -> organization into capillary tubes


Which cells produce Tumor Necrosis Factor (TNF)?

  • Macrophages
  • Mast cells
  • CD4 lymphocytes
  • NK cells
  • T lymphocytes


What functions does TNF have?

  • Stimulates fibroblastic proliferation
  • Stimulates synthesis of collagen
  • Stimulates phagocytosis, chemoattractant for neutrophils
  • Promotes expression of adhesion molecules on endothelial cells - helps neutrophils migrate
  • Promotes fever
  • Promotes lipid/protein mobilization and suppresses appetite
    • Weight loss/anorexia
    • TNF antagonists effective for chronic inflamm disease (RA)


What cells produce Interleukin 1 (IL-1)?

  • Macrophages
  • Monocytes
  • Fibroblasts
  • Dendritic cells


What functions does IL-1 have?

Increases expression of adhesion factors on endothelial cells to enable transmigration of immunocompetent cells (such as phagocytes, lymphocytes, and others) to sites of infx

  • similar to TNF, greater role in fever


What cells produce IL-6? What is its principal action in acute inflamm?

  • Source: Macrophages, other cells
  • Action: Systemic effects (acute phase response)


What cells produce chemokines? What are there principal actions in acute inflamm?

  • Source: Macrophages, endothelial cells, T-lymphocytes, mast cells
  • Action: Recruitment of leukocytes to sites of inflamm; migration of cells in normal tissues


What cells produce IL-17? What are its principal actions in acute inflamm?

  • Source: T lymphocytes
  • Action: Recruitment of neutrophils and monocytes


What cells produce IL-12? What are its principal actions in chronic inflamm?

  • Source: Dendritic cells, macrophages
  • Action: Increased production of IFN-gamma