Wound healing Flashcards
What are the features of first intention healing?
- primary wound healing with primary closure
- sutured incision
- tissue apposition
what are the features of second intention healing?
- open wound healing
2. granulation, contraction, epithelialization
What are the 5 sequence of wound healing
- wounding
- acute vascular phase (bleed)
- inflammatory phase
- cellular phase
- maturation phase
What are the 5 sequence of wound healing
- wounding
- acute vascular phase (bleed)
- inflammatory phase
- cellular phase (fibroplasia?)
- maturation phase (remodelling and maturation)
What changes occur with remodelling and maturation?
- collagen content goes down
- quality of collagen increases
- cross linking between collagen occurs
How long does it take to return to the original tissue strength
it depends on the tissue/original tissue strength
What are the features of the acute vascular phase?
- hemorrhage
2. vasoconstriction (
When a vessel stops bleeding during surgery, what is the cause?
vasoconstriction–the smooth muscle is traumatized and so it contracts (vasospasm) Can be assisted by pressure which helps until clot can form
What are the features of the inflammatory reaction of the inflammatory phase
- localized protective response
- elicited by injury or destruction of tissues
- destroys, dilutes or walls of injurious agent and tissue
- prepares wound for repair process
What are the vascular events of the inflammatory phase
- cellular adhesion
- vasodilation
- increased vascular permeability–inflammatory exudate
What are the vascular events of the inflammatory phase
- cellular adhesion
- vasodilation
- increased vascular permeability–inflammatory exudate
What are the cellular players in the inflammatory phase?
- mast cells
- granulocytes
- platelets
What are the vasoactive substances involved in the inflammatory phase
- histamine
- serotonin
- kinins
- prostaglandins
- chemotactic agents (cytokines?)
What is the role of histamine in the inflammatory phase? How long is it present?
- causes early permeability increase
2.
What is the role of seratonin in the inflammatory phase? When does it have its effect?
- endothelial cell swelling
- induces lysyl oxidase that is responsible for collagen crosslinking during wound healing in the maturation/remodelling phase
- is present later than histamine
What do kinins do in the inflammatory phase
increase capillary permeability
What do prostaglandins do in the inflammatory phase?
- permeability changes
- vasoactive
- chemotaxis
- stimulate mitosis
How do NSAIDs impair healing?
They prevent the production of prostaglandins, which have a role during the inflammatory phase
What are chemotactic agents involved in the inflammatory phase?
- prostaglandins
- lymph node permeability factor
- cytokines
How are granulocytes pH sensitive?
when the pH drops (acidic) they dump their contents, which results in destruction of bacteria, but also destruction of tissue (collagenase, proteolytic enzyme release)
In models with knock out granulocytes, are there changes to wound healing? (if bacterial number is limited)
no
What is the role of granulocytes in a wound?
kill bacteria
Are macrophages necessary for wound healing?
yes
HOw is wound healing (inflammatory phase) localized?
- vasodilation
- leakage
- lymphatics blocked (due to swelling)