Difference between revisions of "Muscle Regeneration"
Jump to navigation
Jump to search
| (One intermediate revision by the same user not shown) | |||
| Line 2: | Line 2: | ||
*Limited array of ways in which to respond to injury | *Limited array of ways in which to respond to injury | ||
| − | **[[ | + | **[[Muscles Degenerative - Pathology#Degeneration|Degeneration]] |
| − | **[[ | + | **[[Muscles Degenerative - Pathology#Necrosis|Necrosis]] |
**Regeneration | **Regeneration | ||
| − | **[[ | + | **[[Muscles Degenerative - Pathology#Atrophy|Atrophy]] |
| − | **[[ | + | **[[Muscles Hyperplastic and Neoplastic - Pathology#Hypertrophy|Hypertrophy]] |
*Large number of factors indicing the changes above, e.g.: | *Large number of factors indicing the changes above, e.g.: | ||
| Line 31: | Line 31: | ||
**If these conditions are not met (e.g. severe thermal damage) '''fibrosis''' will occur | **If these conditions are not met (e.g. severe thermal damage) '''fibrosis''' will occur | ||
*Stages: | *Stages: | ||
| − | #Nuclei in [[ | + | #Nuclei in [[Muscles Degenerative - Pathology#Necrosis|necrotic segement]] disappear, hyalinased sarcoplasm due to loss of normal myofibrillar structure, may separate from adjacent normal myofibrils and/or [[Muscles Degenerative - Pathology#Calcification|mineralise]] |
#Monocytes from capillaries -> macrophages in necrotic portion, satellite cells swell -> vesicular with prominent nucleoli -> mitosis (within 1-4 days after initial injury) | #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 | #Satellite cells move to centre | ||
| Line 40: | Line 40: | ||
*Regeneration by '''budding''' | *Regeneration by '''budding''' | ||
**When conditions are not optimal, disrupted sacrolemma | **When conditions are not optimal, disrupted sacrolemma | ||
| − | **E.g. injection of irritating substance, trauma, [[ | + | **E.g. injection of irritating substance, trauma, [[Muscles Degenerative - Pathology#Ischaemia|infarction]] |
**Myoblasts proliferate -> sacrolamma bulges from cut part -> club-shaped with numerous central nuclei = muscle giant cells | **Myoblasts proliferate -> sacrolamma bulges from cut part -> club-shaped with numerous central nuclei = muscle giant cells | ||
*Monophasic lesions - all at same phase above | *Monophasic lesions - all at same phase above | ||
Revision as of 17:43, 3 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