Muscle Injury: Tissue Healing & Repair (S1)
No description yet. This curated deck is ready for daily study.
Card preview (23)
Tissue healing comprises of regeneration and repair. What is the difference between these two things?
• Regeneration = new replacement muscle fibres • Repair = scar tissue
What are the 4 main stages of tissue healing?
• Bleeding • Inflammation • Proliferation • Remodelling
How long does bleeding occur for?
Follows soft tissue injury, can last up to a few hours - depends on nature of tissue and injury.
Why do we bleed?
Bleeding is an inflammatory mediator?
Inflammation is essential for muscle injury repair. What are the 3 main stages of interactions and reactions?
• Vascular • Cellular • Chemical
How long does inflammation last?
For up to 1-3 days following bleeding
What constitutes the vascular events in the inflammatory response?
• Increased vasodilation + vasopermeability • Increased flow volume • Increased exudate • TISSUE OEDEMA
What constitutes the cellular events in the inflammatory response?
• Attraction of phagocytes/neutrophils, monocytes, lymphocytes etc • Increased phagocytosis • Phagocytosis of debris -> chemical release
What are 4 main possible outcomes of inflammation?
• Resolution • Repair/healing • Suppuration/infection • Chronic inflammation
What stimulates the proliferative phase?
The release of mediators from inflammation
What is proliferation?
The generation and deposition of granulation tissue
What is the onset of proliferation?
24hrs and then peaks between 2-3 weeks, can occur for months.
What are the key events in proliferation?
• Fibroplasia • Angiogenesis • Inc in extracellular collagen production • Myofibroblasts cause wound contraction to minimize scar • Complex interactive response amongst cells + chemical mediators
What happens during fibroplasia?
Fibroblasts and endothelial cells migrate into damaged tissue from adjacent areas, they proliferate and increase activity as well as lay down collagen.
What is angiogenesis?
The formation of new local circulation, to provide more oxygen and nutrients whilst removing metabolic and repair waste products.
What are 3 signs of proliferation?
• Redness - formation of inc no. capillaries • Swelling - from increased no. capillaries • Pain - from pressure-sensitive nerve endings
What are the key events in remodelling?
• Orientation of collagen fibres • Collagen transition: type I replaced type III collagen • Capillaries diminish in number • Tensile strength increases
How long does remodelling last?
Final remodelling will continue for months, and typically at least a year from the initial damage
What are examples of general risk factors known to delay healing?
• Injury history • Fatigue/Overuse • Age • Protein deficiency • Lower temp • Medication use (NSAID abuse) • Mechanical problems • Disease • High risk sport/activities
What are examples of local risk factors known to delay healing?
• Inadequate nutrition • Ongoing inflammation • Drying of the wound • Excessive movement
What is a direct cause of muscle injury?
Trauma (eg sport)
What are some indirect causes of muscle injury?
• Fatigue/overuse -> repetetive microdramage exceeds body’s ability to repair eg. shin splints, tennis elbow, compartment syndrome • Infection • Ischemia • Neurological
Name some methods of investigation for muscle injury
• MRI • Diagnostic ultrasound