Flashcards in Lecture 4 Tissue repair and injury Deck (21):
What is needed for regeneration?
Tissue with high proliferation, viable stem cells and intact connective tissue (scaffolding)
Combination of regeneration and scar formaiton
What does repair rely on?
Capacity to regenerate, extent of injury and extent of scaring.
Examples of regeneration
Liver regeneration after partial hepatectomy, superficial skin wounds, resorption of exudate in lobar pneumonia.
Examples of repair
Deep excisional wounds, myocarium infaction
Examples of fibrosis
Chronic inflam diseases, cirrhosis, pancreatitis, pulmonary fibrosis.
2 limited examples of true regeneration?
epithelium following superficial skin injury & bone after fracture.
Example of hypertrophy to compensate
Nephrons following nephrectomy
Example of hyperplasia to compensate
Hepatocytes following partial hepatectomy
Fibro-proliferative response is when
Deposition of collagen and ECM component (scar). "patches" tissue.
Sequence of healing 5 steps?
Inflam, angiogenesis, migration & prolife of parenchymal cells &fibroblasts, scar, connective tissueremodelling.
When healing a larger scab what happens to the inflammation?
More nacrotic debris, exudate and fibrin to remove -> inflam more intense
Define granulation tissue
New connective tissue with tiny blood vessels
What does a larger amount of granulation tissue mean?
a larger defect. Involves wound contraction
What local factors affect wound healing?
Size, location (how well its vascularised), type (infectious/necrotic/traumatic), infections.
What systemic factors affect would healing?
Nutritional status, metabolic status (diabetes), circulatory/vascular status, hormones (glucocorticoids).
What can complicate repair?
Deficient scar formation -> wound dehiscence (wound ruptures along surgical line)
Excessive repair complications (3)
Excessive granulation tissue (proud flesh), excessive collagen accumulation (hypertrophic scar), Keloid.
area of irregular fibrous tissue formed at the site of a scar or injury