Wound healing Flashcards
When is healing initiated
when inflammation begins. it occurs with a combination of regeneration and repair.
What is regeneration
it is the replace damaged tissue with native tissue. it depends on regenerative capacity of tissue and are divided into 3 regenerative capacity.
What are the 3 tissues of regeneration
liable, stable and permanent
What is labile
continuously cycle to regenerate tissue. they have stem cells that continue to regnerate. examples: small and large bowel, skin and bone marrow
What is stable
are quiescent but can renter the cell cycle. examples are liver through hyperplasia.
What is permanent
lack regenerative potential. ex. skeletal, myocardium and neurons
What is the first phase of repair
granulation tissue
What does granulation tissue have
granulation tissue that contains fibroblast (type 3 collagen), capillaries( provide nutrient) and myofibroblast (contact wound).
What happens to granulation tissue
it forms a scar
How does granulation tissue form a scar
it does this with changing the type 3 collagen to type 1 collagen through collagenase that removes type 3 and requires zinc to happen.
What is the mechanism of regeneration and repair
mediated by paracrine signaling through growth factors. interaction of factors with the receptors results in gene expression and cellular growth
What are the types of collagen again
type 1 collagen- bone
type 2 collagen - cartilage
type 3 collagen - blood vessel and granulation - needs to stretch
type 4 collagen - Basement membrane
What is primary union
where the wound edges brought together for minimal scar formation
What is secondary union
edges are not approximated and the granulation tissue fills in the defect. this results in big scar and causes contraction of the wound.
What is delayed wound healing
what there is a wound that doesn’t healing in the typical time that it should.
