Wound Healing Flashcards
What systemic factors positively affect wound healing?
Good nutritional status
Good general health
What systemic factors negatively affect wound healing?
Infection
Impaired immunity
Poor blood supply
Systemic conditions
What local factors positively affect wound healing?
Good blood supply
Freedom from contamination
What local factors negatively affect wound healing?
Presence of microbes
Presence of foreign bodies
Presence of toxic chemicals
What are the two categories of wounds?
Superficial (non-bleeding)
Deep (bleeding)
What is primary wound healing?
Closure - common following surgery
What is a secondary wound healing?
Wound edges are distant from each other
What are the three stages of wound healing in the order they occur?
Inflammatory stage
Proliferative stage
Remodelling stage
What is Haemostasis and at which stage of healing does it occur?
Body tries to stop the blood from flowing and occurs in the inflammatory stage
What substance causes the blood vessels to narrow as part of haemostasis?
5-Hydroxytryptamine
What are the 3 stages of the inflammatory response
Haemostasis
Platelet activation
Blood coagulation
What type of homeostatic control mechanism is Platelet activation an example of?
Positive Feedback loop
What substance is produced when platelets clump as part of the platelet activation stage of the inflammatory response?
ADP
As well as platelets what other substance is involved in forming a plug during the platelet activation stage?
Sub endothelial collagen
What action does thrombin carry out as part of coagulation?
It converts inactive fibrinogen into fibrin
What function does fibrin perform in coagulation?
It stabilises the clot (3 dimensional meshwork)
What are chemo attractants?
Growth factors released by platelets to attract Neutrophils and Macrophages to the site of a wound
What is diapedesis and why does it occur during the inflammatory response?
The passage of blood cells through intact capillary walls. It occurs so that WBCs attracted by Growth factor can leak into the wound and attempt to kill any bacteria present
Approximately how long after tissue injury do macrophages reach the site of the wound?
24 hours
What do macrophages entering a wound site release and how does this help healing?
Growth factors which initiate the formation of granulation tissue and angiogenesis
What is angiogenesis?
The formation of new blood vessels
At what stage of wound healing does angiogenesis occur?
Inflammatory stage
What role do fibroblasts have in the wound healing process?
They produce collagen fibres and may also have a role in angiogenesis
What are the four types of exudate?
Serous
Fibrinous
Haemorrhagic
Purulent
Why do keratinocytes release proteases during the proliferative stage of wound healing?
To prevent over granulation of the wound. They debride the wound
What happens in the remodelling phase?
Wound closes
Cells undergo apoptosis
Tissue continuously remodelled
Scarring can occur
Is scar tissue as strong as non-wounded tissue?
No, it is only 80% as strong
What are three types of problems affecting wound healing that lead to chronic wound?
Ischaemia
Bacterial colonisation
Impaired neo-angiogenesis
If there are lots of inflammatory cytokines at the site of a wound will this positively affect healing?
No too many will lead to an exaggerated inflammatory response and delay healing
If there are lots of proteases released during the proliferative stage will this lead to a delay in wound healing?
Yes, they will prevent the wound from healing
If there is insufficient oxygen to the wound, will this promote or delay healing?
Delay healing
If there are insufficient growth factors released by platelets and macrophages will this promote or delay healing?
Delay healing
