What is the term for regeneration of injured tissue by replacement with cells of the identical type?
What are the 2 conditions of parenchymal regeneration?
capacity for parenchymal regeneration, CT framework is maintained
Which type of cells proliferate throughout life and regenerate after injury? 2
labile, continuously dividing cells
What are examples of stable cells? 7
liver, kidney, lung, pancreas, smooth muscle, fibroblasts, endothelium
What are the 4 factors favoring fibrosis?
prolonged injury, loss of basement membranes, lots of exudate, lack of renewable cell population
What are the 2 consequences of fibrosis?
loss of functional parenchymal tissue, alteration of physical properties of tissue
How long does it take fibroblasts and vascular EC to proliferate? granulation tissue?
24 hours, 3-5 days
What are the 2 characteristic histological features of granulation tissue?
proliferation of new BV and fibroblasts
What are the 4 zones of granulation tissue?
necrosis/fibrin, MO/capillaries, capillaries/fibroblasts, mature CT
What is the zone of granulation tissue that has a superficial area of variable thickness?
necrosis debris and fibrin
What is the zone of granulation tissue with cleanup, angiogenesis and neovascularization?
macrophages and in-growing capillaries
What is the zone of granulation tissue where young BV from mature vessels that grow perpendicular to the surface of the defect?
proliferating capillaries, fibroblasts
What zone of granulation tissue represents the oldest portion of the healing process?
mature fibrous CT
what are the 4 steps needed for angiogenesis?
degradation of bm, migration of EC, proliferation of EC, maturation of EC
What is the term for the process by which the amount of collagen deposition is increased?
What are the 4 steps that happen in maturation of granulation tissue?
granulation tissue matures, collagen and ground substance are deposited, granulation bed contracts as it matures, specialization of fibroblasts to contractile cells
What is the term for a process including CT replacement and regeneration by which restoration of tissue continuity is achieved?
What happens in healing by 2nd intention?
granulation tissue replaces fibrin and necrotic debris in the wound
What are the 9 steps of skin healing?
clot, restore epithelim, EC lose contact, inflammation, neovascularization, fibroblasts, devascularization, egress of inflammation and fibroblasts, scar
what type of healing happens in kidneys with destruction of the ECM? how long for function?
scar formation and incomplete regeneration, 4 weeks
What happens to lungs when the inflammation cells don't lyse the alveolar exudate? 2
granulation tissue with intra-alveolar fibrosis
What happens in a puncture wound in the brain? 2
fibrous core derived from meninges, perivascular adventitia