Difference between revisions of "Muscle Regeneration"
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| − | + | ===Response to injury=== | |
| − | | | + | |
| − | | | + | *Limited array of ways in which to respond to injury |
| − | + | **[[:Category:Muscles - Degenerative Pathology|Degeneration]] | |
| − | | | + | **[[Muscle Necrosis|Necrosis]] |
| − | | | + | **Regeneration |
| − | | | + | **[[Muscle Atrophy|Atrophy]] |
| − | + | **[[Muscle Hypertrophy|Hypertrophy]] | |
| − | + | ||
| − | + | *Large number of factors indicing the changes above, e.g.: | |
| + | **Trauma | ||
| + | **Toxins | ||
| + | **Infectious agents | ||
| + | **Nutritional deficiencies | ||
| + | **Ichaemia | ||
| + | **[[:Category:Muscles - Developmental Pathology|Hereditary diseases]] | ||
| + | |||
| + | |||
| + | |||
| + | *Specific diagnosis is often not possible based on morphological or histological features alone | ||
| + | *Additional tests, clinical information and history are often required | ||
| + | |||
| + | ===Regeneration=== | ||
| + | [[Image:Muscle regeneration.jpg|right|thumb|100px|<small><center>Muscle regeneration (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]] | ||
| + | |||
| + | *Skeletal muscle myofibres have substantial regenerative ability | ||
| + | *Success depends on: | ||
| + | **An intact '''sarcolemmal tube''' - to act as a support and guide | ||
| + | **Availability of '''satellite cells''' - to act as progenitor cells for new sarcoplasm production | ||
| + | **Macrophages to clear up cell debris | ||
| + | **If these conditions are not met (e.g. severe thermal damage) '''fibrosis''' will occur | ||
| + | *Stages: | ||
| + | #Nuclei in [[Muscle Necrosis|necrotic segement]] disappear, hyalinased sarcoplasm due to loss of normal myofibrillar structure, may separate from adjacent normal myofibrils and/or [[Muscle Calcification|mineralise]] | ||
| + | #Monocytes from capillaries -> macrophages in necrotic portion, satellite cells swell -> vesicular with prominent nucleoli -> mitosis (within 1-4 days after initial injury) | ||
| + | #Satellite cells move to centre | ||
| + | #Macrophages clear the sacrolemmal tube, plasmalemma disappears, shape maintained by basal lamina | ||
| + | #Satellite cells -> myoblasts (contain myosin) -> fuse forming myotubes with row of central nuclei; cytoplasmic processes fusing | ||
| + | #Growing and differentiating fibre, striations appear - formation of sarcomeres | ||
| + | #Nuclei move to peripheral position (2-3 weeks after initial injury) | ||
| + | *Regeneration by '''budding''' | ||
| + | **When conditions are not optimal, disrupted sacrolemma | ||
| + | **E.g. injection of irritating substance, trauma, [[Muscle Ischaemia|infarction]] | ||
| + | **Myoblasts proliferate -> sacrolamma bulges from cut part -> club-shaped with numerous central nuclei = muscle giant cells | ||
| + | *Monophasic lesions - all at same phase above | ||
| + | |||
| + | |||
| + | |||
| + | [[Category:Muscles - Pathology]] | ||
Latest revision as of 11:41, 7 March 2011
Response to injury
- Limited array of ways in which to respond to injury
- Degeneration
- Necrosis
- Regeneration
- Atrophy
- Hypertrophy
- Large number of factors indicing the changes above, e.g.:
- Trauma
- Toxins
- Infectious agents
- Nutritional deficiencies
- Ichaemia
- Hereditary diseases
- Specific diagnosis is often not possible based on morphological or histological features alone
- Additional tests, clinical information and history are often required
Regeneration
- Skeletal muscle myofibres have substantial regenerative ability
- Success depends on:
- An intact sarcolemmal tube - to act as a support and guide
- Availability of satellite cells - to act as progenitor cells for new sarcoplasm production
- Macrophages to clear up cell debris
- If these conditions are not met (e.g. severe thermal damage) fibrosis will occur
- Stages:
- Nuclei in necrotic segement disappear, hyalinased sarcoplasm due to loss of normal myofibrillar structure, may separate from adjacent normal myofibrils and/or mineralise
- Monocytes from capillaries -> macrophages in necrotic portion, satellite cells swell -> vesicular with prominent nucleoli -> mitosis (within 1-4 days after initial injury)
- Satellite cells move to centre
- Macrophages clear the sacrolemmal tube, plasmalemma disappears, shape maintained by basal lamina
- Satellite cells -> myoblasts (contain myosin) -> fuse forming myotubes with row of central nuclei; cytoplasmic processes fusing
- Growing and differentiating fibre, striations appear - formation of sarcomeres
- Nuclei move to peripheral position (2-3 weeks after initial injury)
- Regeneration by budding
- When conditions are not optimal, disrupted sacrolemma
- E.g. injection of irritating substance, trauma, infarction
- Myoblasts proliferate -> sacrolamma bulges from cut part -> club-shaped with numerous central nuclei = muscle giant cells
- Monophasic lesions - all at same phase above