Healing and repair Flashcards
What are the four stages of healing?
Clotting Phase
Inflammation Phase
Proliferative phase
Maturation Phase
What are labile cells?
Allow rapid regeneration for cell repair
What are stable cells?
Have variable states of regeneration, rapid proliferation in response to injury
What are permanent cells?
Unable to divide and regenerate
What is an example of permanent cells in oral cavity?
Nerve fibres
What is an example of labile cells in the oral cavity?
Oral keratinocytes
What is an example of stable cells in the oral cavity?
Oral fibroblasts
STAGES IN HEALING
What is formed during the proliferative phase?
Granulation tissue
What makes up new tissue during the proliferative phase?
Fibroblasts
What is meant by angiogenesis?
The formation of new blood vessels
What else, other than fibroblasts, is essential in the formation of granulation tissue?
Growth factors
What is involved during the first phase of forming granulation tissue?
Mix of proliferating capillaries, fibroblasts and immune cells
These capillaries are very leaky allowing cells and fluid into tissue
What does the second phase of the formation of the granulation tissue involve?
Mature fibroblasts lay down collagen
What is the growth factor produced by innate immune cells?
Vascular endothelial growth factor (VEGF)
What are the two mechanisms of angiogenesis?
Sprouting
Intussusceptive (splitting)
What are functions of growth factors?
-Promote cell survival
-Angiogenesis
-Locomotion
-Contractility
What is fibrosis?
The deposition of collagen to form of fibrous connective tissue
What is fibrosis driven by?
Fibroblasts and macrophages
What macrophage subtypes control fibroblast function during fibrosis?
M1 and M2
What growth factors do M2 macrophages produce?
Transforming growth factor BETA (TGFB)
Platelet derived growth factor (PDGF)
What occurs during the maturation phase?
Tissue remodelling
How much of pre injury strength is regained during the maturation phase?
80%
What are the three stages of fracture healing?
Inflammatory stage
Repairing stage
Remodelling phase
What happens during the inflammatory stage in fracture healing?
A hematoma is formed, bone cells are completely derived of oxygen and blood and die
What is a hematoma?
Blood clot formation in hard tissue
What happens during stage 1 of the repairing stage in fracture healing?
Capillaries form into the hematoma
Fibroblasts produce collagen
Osteoblasts form spongy bone
Granulation tissue is formed and becomes fibrocartilage callus
What happens during stage 2 of the repairing stage in fracture healing?
Chondrocytes and osteoblasts produce cartilage and bone
Granulation tissue is ossified
Formation of hard bone callus (woven bone)
What happens during the remodelling stage during fractured healing?
Osteoclasts and osteoblasts remodel the hard bone callus
Cortical bone replaces woven bone
Angiogenesis is essential
