Muscle injury- principles of Tissue healing and repair Flashcards
What are the processes of Regeneration and Repair with regards to tissue healing
- Regeneration= tissue is replaced by the formation of surrounding undamaged cells in a ‘like for like’ basis.
- Repair= Damaged tissue is replaced through granulation tissue to form mature scar tissue
What are the four main phases to muscle healing and in what order they occur.
1) Bleeding,
2) Inflammation,
3) Proliferation,
4) Remodelling.
What is the bleeding and inflammation phase sometimes referred as?
The ‘Degeneration’ phase
What is the proliferation phase sometimes known as?
The Regeneration phase
How long does the Bleeding phase usually last for?
- Usually starts after the injury and continues for about 6-8 hours.
- In rare occasions such as a crush injury to the higher vascular muscle tissue bleeding can last 24 hours
Key things about the bleeding phase
- Usually lasts for 6-8 hours,
- blood cells and plasma are released into the wound site along with other factors such as ATP.
- Also there is an exposure of collagen fibres, this process upsets the homeostasis within the tissue and triggers a cascade of events so an early clot is formed to prevent bleeding.
What are the key signs of inflammation?
- Redness,
- Heat,
- Swelling,
- Pain,
- Loss of function.
Key things about the inflammation stage
- The First aim is to stop bleeding hence there are some obvious cross-overs with the bleeding phase and why they are often considered a single stage.
- During this phase there are multiple vascular, cellular and chemical interactions and reactions.
- Inflammation stage lasts a few days average about 6 days
In what position does the proliferation stage occur in regards to muscle/tissue healing
-It comes third after the inflammation stage.
Key things about the proliferation phase
- It is the third stage of healing,
- Is also known as the ‘regeneration phase’,
- Starts as soon as soon as 24 hours post injury and can last 2-3 weeks.
- Stage is characterised by deposition of healing material and the onward ‘clean up’ of damaged tissue,
- Four key events are:
- Fibroplasia,
- Angiogenesis,
- Increase in extracellular collagen production,
- Myofibroblasts cause wound contraction to minimise scar.
What are the key 4 events that take place during the proliferation phase?
1) Fibroplasia,
2) Angiogenesis,
3) Increase in extracellular collagen production,
4) Myofibroblasts cause wound contraction to minimise scar.
In what position does the remodelling phase occur in regards to muscle/ tissue healing
-Its the last stage and comes after the proliferation stage.
Key things about the remodelling phase.
- Its the final phase of healing,
- This phase can last for weeks, months or even years,
- During the phase maturation of collagen structure and arrangement occurs and hopefully results in an organised and functional scar.
- Key events occurring during this phase include:
1) Orientation of collagen fibres,
2) Collagen deposition type 1 replaces type 3 collagen,
3) Capillaries diminish in number,
4) Tensile strength increases - At this stage there should be reduced redness and reduced pain
What are the 4 key events that occur during the remodelling phase
1) Orientation of collagen fibres,
2) Collagen deposition type 1 replaces types 3 collagen,
3) Capillaries diminish in number,
4) Tensile strength increases
What are some of the factors that affect the health of tissues and hence their capacity to withstand tensile stress.
- History of injury,
- Decreased flexibility,
- Fatigue/overuse,
- Weak muscles,
- Failure to stretch and warm up,
- Disease ,
- High risk activities,
- Increasing age,
- Mechanical dysfunction,
- Medication such as Steroids
