Tissue Repair Flashcards
(26 cards)
Inflammation
Response of vascular tissues to infection and tissue damage that brings cells and molecules of host defense to the site they are needed.
Cardinal signs of inflammation
Calor, Tubor, Rubor, Dolor, functio laesa.
Exudate
Extravascular fluid that has a high protein concentration and contains cellular debris.
Purulent inflammation
Characterized by the production of pus, exudate containing neutrophils, liquified debris and edema fluid. Also called Suppurative. Often caused by pyogenic bacteria.
Abscesses
Localized collections of pus, buried in tissue, organ, or confined space. Seeded by pyogenic bacteria.
Ulcer
Local defect or excavation of the surface of an organ or tissue that is produced by sloughing of inflamed necrotic tissue.
Granulomatous inflammation
Form of chronic inflammation characterized by collections of actrivated macrophages, often with T cells, and sometimes central necrosis. Macrophages may fuse forming multinucleate giant cells.
Langhans Cells
Giant cells that are 40-50 micrometers in diameter.
Causes of Granulomatous inflammation
TB Leprosy Syphilis Cat-Scratch Fever Sarcoidosis Crohn’s disease/ IBD
Labile Tissues
cells are constantly being replaced by new cells derived from tissue stem cells. Hematopoietic stem cells and surface epithelia are an example.
Stable Tissues
Made up of cells that are normally in G0 stage, but are capable of dividing in response to injury or loss of tissue mass. Ex: parenchyma of most solid organs, endothelial cells, fibroblasts, and smooth muscle cells.
Permanent tissues
Terminally differentiated non proliferative cells. Ex: cardiac muscle cells, and neurons.
Steps of Scar Formation
Inflammation
Angiogenesis
Formation of granulation tissue
Remodeling of connective tissue
Classically Activated M1 macrophage
Activated by monocyte producing IFNgamma and TLR ligands. Can produce IL1, TNF, IL12, IL6, and chemokines. Can cause inflammation, and is phagocytically active.
Alternatively activated M2 Macrophage
Activated by monocyte secreting IL13 and IL4. Can secerete IL10 and TGFbeta. Has an anti-inflammatory effect, wound repair, and fibrosis.
Angiogenesis
formation of new blood vessels needed to support the repair process.
Formation fo granulation tissue
Caused by migration and proliferation of fibroblasts and deposition of loose connective tissue. TGFbeta is an important sytokine involved in deposition.
Remodeling of Connective tissue
CT laid down by fibroblasts is reorganized into a fibrous scar. Begins 2-3 weeks after injury.
Healing by first intention/Primary union
Epithelial regeneration with minimal scarring.
Healing by second intention/secondary union
Larger wounds that heal by a combination of regeneration and scarring.
Impairment of tissue repair factors:
Infection Diabetes Nutritional status Steroid use Mechanical factors Poor perfusion Foreign bodies Location, type and extent of injury.
Dehiscions
Pulling apart of a wound
Hypertrophic scar
Accumulation of excessive amounts of collagen results in a raised scar.
Keloid scar
Scar tissue that grows beyond the boundaries of the original wound without regression.
