Repair and Regeneration (8) Flashcards
Healing by regeneration
Damaged cells replaced by like-tissues, returns to normal
Healing by repair
Damaged cells cannot be replaced by like fibrosis and scarring, loss of specialised function
Labile cell populations
High turnover, excellent regeneration (epithelia)
Stable/quiescent cell populations
Low turnover, can increase regeneration (liver, renal tubules)
Permanent cell populations
No turnover/regneration (neurones and muscle cells)
Stem cells
Prolonged self-renewal, asymmetric replication, crucial for regeneration, can have destruction of anatomical ‘niche’ (full thickness burns/radiation)
Control of regenration
Proliferation of stem cell, covering of defect, contact inhibition, complex control by growth factors (cell-cell and cell-matrix interactions)
Contact inhibition
Proliferate until touch each other
Repair by granulation tissue
Contains new capillary loops, neutrophils, macrophages, (myo) fibroblasts
(myo) fibroblasts
Lay down matrix components e.g. connective tissue, can acquire myofibrils and contract wound, synthesise collagen and ECM
Problems with wound contraction
Contractors after burns, oesophageal peptic strictures
Local factors inhibiting healing
Infection, haematoma, blood supply, foreign bodies, mechanical stress
System factors inhibiting healing
Age, drugs (steroids), anaemia, diabetes, malnutrition, catabolic states, vit C deficiency, trace metal deficiency
Healing by first intention
Clean, uninfected surgical wound, good haemostats, edges opposed (sutures/staples), can cause haematoma > bigger function destroyed
Healing by second intention
Wound edges not apposed, extensive tissue loss, apposition not physically possible, large haematoma, infection, foreign body, more florid granulation tissue reaction, more scarring
