Healing Flashcards
What are the 4 steps of tissue response to injury
Acute inflammation (transient inciting stimulus)
Demolition (removal)
Healing/repair
Resolution
What is repair
What is the end product formed
It means replacement of lost tissue with granulation tissue
It finally matures to form fibrous tissue (scar)
What are the component of granulation tissue
Proliferating capillaries
Macrophages
Fibroblast, myofibroblast
What is regeneration
Replacement of the damaged tissue with similar tissue type, and invovles proliferation of neighbouring undamaged specialized cells
How can we classify cells according to their regenerative capacity
Labile
Stable
Permanent
What stage are the stable cells always at
G0 phase
What are the steps for Wound healing
⎼Migration and regeneration of parenchymal cells (functional cell)
⎼Migration and proliferation of connective tissue cells
⎼Synthesis of extracellular matrix proteins
⎼Remodeling of connective tissue and
parenchyma
⎼Collagenization and acquisition of wound
strength
What are the growth factors released to aid wound healing
Vascular endothelial growth factors (VEGFs)
—-> Grow new vessels
Fibroblast growth factors (FGFs)
Transforming growth factor-β (TGF-β)
mitogenesis e.g. EGF
What is the Cell-cell and cell-matrix interaction
cells capable of regenerating, stop proliferating after the defect caused by injury has been healed
What are the details in Extracellular matrix synthesis and collagenization
–> fibroblasts secrete extracellular matrix components
–> proteoglycans, type III collagen
–> this is eventually replaced by type I collagen to form a permanent scar
What are the details of Skin Wounds
–Formation of “scab” and acute inflammation
–Regeneration of epithelial covering and
formation of granulation tissue
–Deposition of collagen and resorption of
capillaries
–Formation of scar
What is the healing process of Epithelial ulceration
Similar to that of Skin wound healing
What is the steps for Bone fracture
⎼Haematoma formation and inflammation
⎼Demolition
⎼Granulation tissue formation
⎼Callus formation
⎼Formation of lamellar bone
⎼Remodelling
What is haematoma
Local bleeding outside blood vessel
What is callus
What forms it
What is it’s function
Other than the cell forming the callus, what else will be active to remodel the bone
A soft callus (a type of soft bone) replaces the blood clot that formed in the inflammatory stage.
Osteoblast
Bridge the gap between the 2 bone fractures
Osteoclast
What will happen to the callus with the aim to harden it
Mineralization
What will replace the Callus afterwards
Laminar bone
What is meant by primary intention healing
To seal the wond / cut directly
What is healing by secondary intention
Open wound
What is the differenfce between healing by secondary and primary intention
Healing by secondary intention involves:
⎼ greater tissue loss
⎼more inflammatory exudate and necrotic
material to remove
⎼more granulation tissue
⎼wound contraction
-Slower process
-Increased Liability to infection
What are the factors that affect healing
Local Factors
– Type of wound
– Apposition of wound margin
– Blood supply
– Infection
– Presence of foreign body in wound
– Previous irradiation
What conditons will have adverse effect on wound healing
⎼ poor nutrition
* protein deficient
* Vitamin C deficient
⎼ steroid administration
⎼ systemic diseases
* diabetes mellitus, renal failure, cachexia
What physical agent can accelerate healing
UV light
Name 7 complications of wound healing
Infection
Keloid formation
Weak scar
Painful scar
Pigmentization
Wound Dishiscence (爆綫）
Cicatrization (the contraction of fibrous tissue formed at a wound site by fibroblast)
What is the complication for lung tissue if acute inflammation occurs with extracellular matrix intact?
It becomes normal after regeneration
What is the complication for lung tissue if extracellular matrix is damaged?
It undergoes fibrosis to cause interstitial fibrosis
What is the complication if the heart has acute inflammation
It undergoes fibrosis to cause myocardial scar
If the Liver has its tissue architecture damaged, what is the complication
Cirrhosis
What are the regenerative capacity of cartilage and tendon respectively
Poor
Good but slow
What is the regenerative capacity of muscle
None in cardiac muscle
Skeletal muscle regenerate by “Satellite cell”
smooth muscle have greatest capacity
Are mature neurons regenerative
What is the complication brought by nerve transection
How can the neuronal connection be re-estabilished
No as they are permanent cell
Wallerian degeneration
re-growth and re-organization of cell processes of surviving neurons
What does Wallerian degeneration consist of
What does Regeneration involves
Total degeneration of axon and secondary demyelination
Regeneration involves
* Schwann cell proliferation and sprouting of axons
What are the 2 important properties of Stem cells
self-renewal, asymmetric division
How to obtain embryonic stem cell
Obtained from inner cell mass of blastocyst 4 days after fertilization
What are the 5 properties of Embryonic Stem Cells
– Versatile and can be cultured more rapidly
– More difficult to induce into the specific tissues
desired
– Risk of rejection as foreign tissue
– Danger of forming tumors
– Danger of transmission of infection
What is the 4 property of adult stem cell
⎼More finite life span
⎼Easier to coax into specialization
⎼Less risk of uncontrollable growth of tumors
⎼Less risk of immune rejection
Which type of stem cell has no sucessful case in human treatment
Embryonic stem cell
