Tissue Repair Flashcards
Proliferation of cells and tissues to replace lost structures
Regeneration
Tissue response to injury consisting of regeneration and fibrosis or connective tissue deposition (scar formation)
Repair
Extensive deposition of collagen in the setting of chronic inflammation, severe injury, and permanent damage
Fibrosis (scarring)
Regenerative capacity:
- continuously lost and replace (proliferating of residual cells or maturation of stem cells)
- exhibited by surface epithelium, hematopoietic stem cells
Labile
Regenerative capacity:
- maintained in a state of quiescence (G0 in cell cycle)
- limited capacity to proliferate (except hepatocytes)
- proliferate in response to injury or tissue loss
- exhibited by liver, kidney, pancreas, endothelium, fibroblasts, smooth muscle
Stable
Regenerative capacity:
- terminally differentiated (left the cell cycle)
- non-proliferating
- exhibited by neurons, striated muscle
Permanent
First step of repair by connective tissue deposition, involving the formation of new blood vessels from existing ones via growth factor VEGF
Angiogenesis
(3 steps of repair by connective tissue deposition
- Angiogenesis
- Formation of granulation tissue
- Remodelling of scar)
Second step of repair by connective tissue deposition, involving fibroblasts and loose connective tissue from the extracellular matrix, with continuing angiogenesis and infiltration of infammatory cells (hallmark of repair)
Formation of granulation tissue
(3 steps of repair by connective tissue deposition
- Angiogenesis
- Formation of granulation tissue
- Remodelling of scar)
Third and final step of repair by connective tissue deposition, involving the formation of the fibrous scar, balancing ECM degradation by metalloproteinases and ECM protein synthesis by tissue inhibitorso of metalloproteinases (TIMPs)
Remodelling of scar
(3 steps of repair by connective tissue deposition
- Angiogenesis
- Formation of granulation tissue
- Remodelling of scar)
The “central cell” in tissue repair, producing PDGF, FGF2, and TGF-b
Macrophage
7 factors that impede tissue repair
- Infections
- Diabetes mellitus
- Vitamin C deficiency
- Glucocorticoids (inhibit TGF-b)
- Pressue
- Poor perfusion
- Foreign bodies
Abnormality in tissue repair formed from the inadequacy of granulation tissue formation
Wound dehiscence and ulcer
Abnormality in tissue repair formed from the excessive formation of repair components
Keloids and hypertrophic scars
Abnormality in tissue repair formed from exuberant granulation tissue
Proud flesh
Abnormality in tissue repair formed from excessive wound contraction
Contracture
Cell cycle checkpoint for DNA damage
G1/S checkpoint
Cell cycle checkpoint for damaged/unduplicated DNA
G2/M checkpoint
Collection of molecules secreted by the cellular environment whose main functions are as follows:
- mechanical support
- control of cell proliferation
- scaffolding for tissue renewal/repair
- establishment of tissue microenvironment
- storage and presentation of regulatory molecules
- forms the interstitial matrix and the basement membrane
- made of fibrous structural proteins (collagen, elastin), water-hydrated gels (proteoglycan, hyaluronan), and adhesive glycoproteins (fibronectin, BM laminin, integrin)
Extracellular matrix (ECM)
Most abundant protein in the human body that organizes and strengthens the ECM, extensively modified, and the only protein that undergoes FINAL modification in the rough endoplasmic reticulum (not in the Golgi apparatus)
Collagen
Collagen type most associated with bone, skin, tendon, dentin, fascia, cornea, and LATE WOUND REPAIR
Collagen type 1
(Mnemonic: Type 1 - bONE, sk1n, tendONE, dent1n, fasc1a Type 2 - carTWOlage Type 3 - reTHREEculin Type 4 - "under the floor", BM)
Collagen type most associated with cartilage (includine hyaline), vitreous body, nucleus pulposus
Collagen type 2
(Mnemonic: Type 1 - bONE, sk1n, tendONE, dent1n, fasc1a Type 2 - carTWOlage Type 3 - reTHREEculin Type 4 - "under the floor", BM)
Collagen type most associated with reticulin, blood vessels, uterus, fetal tissue, GRANULATION
Collagen type 3
(Mnemonic: Type 1 - bONE, sk1n, tendONE, dent1n, fasc1a Type 2 - carTWOlage Type 3 - reTHREEculin Type 4 - "under the floor", BM)
Collagen type most associated with the basement membrane and basal lamina
Collagen type 4
(Mnemonic: Type 1 - bONE, sk1n, tendONE, dent1n, fasc1a Type 2 - carTWOlage Type 3 - reTHREEculin Type 4 - "under the floor", BM)
Healing that involves only the epithelial layer - primary mechanism is EPITHELIAL REGENERATION
Healing by first intention
Healing that involves more extensive cell and tissue loss - mechanism is COMBINATION of epithilial regeneration and scarring
Healing by second intention
