Wound Healing Flashcards
What stimulated wound healing
Macrophages (therefore it is linked to inflammation)
What has to happen for wound healing to occur
Inflammation
What is regeneration
Restitution of tissue components identical to those killed/ lost
What regenerates from stem cells
Liver, kidney, haematopoietic, skin, GI tract
What is essential for wound healing
An intact connective tissue framework, the healing then essentially patches the tissue
Where is scarring
At the compact patches of collagen
What is haemostasis
Clotting
What three phases occur in conjunction with eachother in haemostasis
Vascular phase, platelet phase and coagulation phase
Describe the vascular phase
Damage to blood vessel wall causes contraction in that area of the blood vessel (vasconstriction), can last from 30 minutes- few hours.
What does the vascular phase occur as a result of
Damage to endothelial cells
What does damage to endothelial cells cause the release of
ADP, tissue factor (factor III), prostacyclin, endothelins
What is tissue factor required for
Activation of thrombin from prothrombin
Describe the role of prostacylcin
Kind of a feedback mechanism, this protein actually causes vasodilation and prevents the formation of the platelet plug
Describe the role of endothelins
Primary hormones involved in the vascular phase. They stimulate smooth muscle contraction and stimulate cell division of endothelial cells, smooth muscle cells and fibroblasts this aiding repair of the damaged site
What can occur if damage to the blood vessel is small enough
It can be ‘plugged’ by a platelet plug
What is platelet formation controlled by
TPO (thrombopoietin)
What is TPO mainly produced by
The liver
Describe the platelet phase
Platelet formation controlled by TPO. Platelets attach themselves to the collagen of damaged epithelium and begin to aggregate. Fibrin forms threads which stabilise the plug
What is adhesion
Platelets attaching themselves to the damaged epithelium
What is fibrin produced by
Liver and platelets.
What happens to a platelet when it becomes attached to a damages enothelial surface
It will change its own size and shape
Describe the process of a platelet changing its own size and shape when attached to a damaged endothelial surface
It will swell and become large and irregular. The contractile proteins contract causing the release of granules. ADP, thromboxane and Ca2+ ions are all released
What is the role of ADP, thromboxane and Ca2+
They act on nearby platelets and attract them to the site causing them to adhere to the platelets already present. This creates positive feedback loop causing aggregation of more and more platelets
What are the two types of granules released by the platelets
Alpha and dense