Pathophysiology of Skeletal Muscle Flashcards
1
Q
Plasticity of skeletal muscle: exercise
- muscle is extremely …
- adapts to changes in functional demand: fill in blanks
A
- muscle is extremely plastic
- adapts to changes in functional demand:
2
Q
Endurance exercise responds to total … activity
A
Endurance exercise responds to total contractile activity
3
Q
Resistance training responds to … and …
A
Resistance training responds to loading and stretch
4
Q
Muscle plasticity: adaptations
- adaptations:
- s…
- e.g. size, capillarisation
- … properties
- e.g. fibre type transitions
- s…
- adaptability occurs from … into maturity
A
- adaptations:
-
structural
- e.g. size, capillarisation
-
contractile properties
- e.g. fibre type transitions
-
structural
- adaptability occurs from embryogenesis into maturity
5
Q
… = The formation and development of a network of capillaries to a part of the body
A
Capillarisation = The formation and development of a network of capillaries to a part of the body
6
Q
Structural adaptation
- Total … of muscle fibres … at birth:
- e.g. 200,000 – biceps brachii
- But - muscles can grow: H…
- synthesis of myofilaments
- addition of sarcomeres
- satellite cell activation
- angiogenesis & vascularisation
- some muscles enlarge by between 15-50%
A
- Total number of muscle fibres fixed at birth:
- e.g. 200,000 – biceps brachii
- But - muscles can grow: hypertrophy
- synthesis of myofilaments
- addition of sarcomeres
- satellite cell activation
- angiogenesis & vascularisation
- some muscles enlarge by between 15-50%
7
Q
Structural adaptation
- Total number of muscle fibres fixed at birth:
- e.g. 200,000 – biceps brachii
- But - muscles can grow: hypertrophy
- synthesis of myofilaments
- addition of sarcomeres
- satellite cell activation
- angio… & vascularisation
- some muscles enlarge by between ..-..%
A
- Total number of muscle fibres fixed at birth:
- e.g. 200,000 – biceps brachii
- But - muscles can grow: hypertrophy
- synthesis of myofilaments
- addition of sarcomeres
- satellite cell activation
- angiogenesis & vascularisation
- some muscles enlarge by between 15-50%
8
Q
Structural adaptation
- Total number of muscle fibres fixed at birth:
- e.g. 200,000 – biceps brachii
- But - muscles can …: hypertrophy
- … of myofilaments
- addition of ….
- satellite cell activation
- angiogenesis & vascularisation
- some muscles enlarge by between 15-50%
A
- Total number of muscle fibres fixed at birth:
- e.g. 200,000 – biceps brachii
- But - muscles can grow: hypertrophy
- synthesis of myofilaments
- addition of sarcomeres
- satellite cell activation
- angiogenesis & vascularisation
- some muscles enlarge by between 15-50%
9
Q
Effect of endurance exercise
- e.g. distance running, cycling or swimming (… force, … contractile frequencies)
- … fibre diameter (slight), blood supply ( oxidative capacity), mitochondrial content
- will express increased in oxidative enzymes
- fibres become slower
- gradual transformation of type IIX to type IIA (or to type I?)
A
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- Increased fibre diameter (slight), blood supply ( oxidative capacity), mitochondrial content
- will express increased in oxidative enzymes
- fibres become slower
- gradual transformation of type IIX to type IIA (or to type I?)
10
Q
Effect of endurance exercise
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- Increased fibre … (slight), blood supply ( oxidative capacity), … content
- will express increased in oxidative enzymes
- fibres become …
- gradual transformation of type IIX to type IIA (or to type I?)
A
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- Increased fibre diameter (slight), blood supply ( oxidative capacity), mitochondrial content
- will express increased in oxidative enzymes
- fibres become slower
- gradual transformation of type IIX to type IIA (or to type I?)
11
Q
Effect of endurance exercise
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- Increased fibre diameter (slight), … supply ( oxidative capacity), mitochondrial content
- will express increased in … enzymes
- fibres become slower
- gradual transformation of type … to type … (or to type I?)
A
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- Increased fibre diameter (slight), blood supply ( oxidative capacity), mitochondrial content
- will express increased in oxidative enzymes
- fibres become slower
- gradual transformation of type IIX to type IIA (or to type I?)
12
Q
Effect of endurance exercise
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- … fibre diameter (slight), blood supply ( oxidative capacity), mitochondrial content
- will express increased in oxidative enzymes
- fibres become …
- gradual transformation of type IIX to type IIA (or to type I?)
A
- e.g. distance running, cycling or swimming (low force, high contractile frequencies)
- Increased fibre diameter (slight), blood supply ( oxidative capacity), mitochondrial content
- will express increased in oxidative enzymes
- fibres become slower
- gradual transformation of type IIX to type IIA (or to type I?)
13
Q
Non-endurance exercise
- conversion to type II…
- from type II…
- greater muscle force & strength
- Increase in type II… fibre size due to increase in numbers of sarcomeres & myofilaments
- results in much larger muscles (bulk)
A
- conversion to type IIX
- from type IIA
- greater muscle force & strength
- Increase in type IIX fibre size due to in numbers of sarcomeres & myofilaments
- results in much larger muscles (bulk)
14
Q
Non-endurance exercise
- conversion to type IIX
- from type IIA
- … muscle force & strength
- Increase in type IIX fibre size due to increase in numbers of sarcomeres & myofilaments
- results in much larger muscles (…)
A
- conversion to type IIX
- from type IIA
- greater muscle force & strength
- Increase in type IIX fibre size due to in numbers of sarcomeres & myofilaments
- results in much larger muscles (bulk)
15
Q
Ice and Heat - Exercise
- Ice - To reduce swelling by reducing …
- After an acute injury (s..)
- After exercise in overuse injury
- Heat - To relax and loosen tissues
- Use before activities that irritate chronic injuries (s…)
- Increases blood flow
A
- Ice - To reduce swelling by reducing perfusion
- After an acute injury (Sprain)
- After exercise in overuse injury
- Heat - To relax and loosen tissues
- Use before activities that irritate chronic injuries (Strain)
- Increases blood flow
16
Q
Ice and Heat - Exercise
- Ice - To reduce swelling by reducing perfusion
- After an … injury (Sprain)
- After exercise in overuse injury
- Heat - To relax and loosen tissues
- Use before activities that irritate … injuries (Strain)
- Increases blood flow
A
- Ice - To reduce swelling by reducing perfusion
- After an acute injury (Sprain)
- After exercise in overuse injury
- Heat - To relax and loosen tissues
- Use before activities that irritate chronic injuries (Strain)
- Increases blood flow
17
Q
Ice and Heat - Exercise
- Ice - To reduce swelling by reducing perfusion
- After an acute injury (Sprain)
- After exercise in overuse injury
- Heat - To … and … tissues
- Use before activities that irritate chronic injuries (Strain)
- … blood flow
A
- Ice - To reduce swelling by reducing perfusion
- After an acute injury (Sprain)
- After exercise in overuse injury
- Heat - To relax and loosen tissues
- Use before activities that irritate chronic injuries (Strain)
- Increases blood flow
18
Q
A … is an injury to a ligament, whereas a … is an injury to a muscle or tendon
A
A sprain is an injury to a ligament, whereas a strain is an injury to a muscle or tendon
19
Q
A sprain is an injury to a …, whereas a strain is an injury to a … or …
A
A sprain is an injury to a ligament, whereas a strain is an injury to a muscle or tendon
20
Q
Aspirin and Musculoskeletal Pain
- Aspirin is an … - So is ibuprofen
- Reduces … and …
- Used for musc-skel pain
- Chronic diseases
- Osteoarthritis
- Sports injuries
- Combined with ice
- Often after exercise
- Chronic diseases
A
- Aspirin is an NSAID - So is ibuprofen
- Reduces pain and inflammation
- Used for musc-skel pain
- Chronic diseases
- Osteoarthritis
- Sports injuries
- Combined with ice
- Often after exercise
- Chronic diseases
21
Q
Aspirin and Musculoskeletal Pain
- Aspirin is an NSAID - So is ibuprofen
- Reduces pain and inflammation
- Used for musc-skel pain
- … diseases
- Osteoarthritis
- … injuries
- Combined with ice
- Often after exercise
- … diseases
A
- Aspirin is an NSAID - So is ibuprofen
- Reduces pain and inflammation
- Used for musc-skel pain
-
Chronic diseases
- Osteoarthritis
-
Sports injuries
- Combined with ice
- Often after exercise
-
Chronic diseases
22
Q
Aspirin and Musculoskeletal Pain
- Aspirin is an NSAID - So is ibuprofen
- Reduces pain and inflammation
- Used for musc-skel pain
- Chronic diseases
- Os…
- Sports injuries
- Combined with …
- Often … exercise
- Chronic diseases
A
- Aspirin is an NSAID - So is ibuprofen
- Reduces pain and inflammation
- Used for musc-skel pain
- Chronic diseases
- Osteoarthritis
- Sports injuries
- Combined with ice
- Often after exercise
- Chronic diseases
23
Q
Aspirin and Musculoskeletal Pain - Mechanism
- Inhibits …
- Reduces synthesis of prostaglandins
- Part of … acid pathway
- Arachidonic acid and prostaglandins have many effects
- Gastro-intestinal adverse effects of chronic aspirin
- Stomach bleeding
- Ulcers
- Gastro-intestinal adverse effects of chronic aspirin
A
- Inhibits COX
- Reduces synthesis of prostaglandins
- Part of arachidonic acid pathway
- Arachidonic acid and prostaglandins have many effects
- Gastro-intestinal adverse effects of chronic aspirin
- Stomach bleeding
- Ulcers
- Gastro-intestinal adverse effects of chronic aspirin
24
Q
Aspirin and Musculoskeletal Pain - Mechanism
- Inhibits COX
- Reduces synthesis of …
- Part of arachidonic acid pathway
- Arachidonic acid and prostaglandins have many effects
- …-… adverse effects of chronic aspirin
A
- Inhibits COX
- Reduces synthesis of prostaglandins
- Part of arachidonic acid pathway
- Arachidonic acid and prostaglandins have many effects
-
Gastro-intestinal adverse effects of chronic aspirin
- Stomach bleeding
- Ulcers
-
Gastro-intestinal adverse effects of chronic aspirin
25
Q
Aspirin and Musculoskeletal Pain - Mechanism
- Inhibits COX
- Reduces synthesis of prostaglandins
- Part of arachidonic acid pathway
- Arachidonic acid and prostaglandins have many effects
- Gastro-intestinal adverse effects of chronic aspirin
- … bleeding
- U..
- Gastro-intestinal adverse effects of chronic aspirin
A
- Inhibits COX
- Reduces synthesis of prostaglandins
- Part of arachidonic acid pathway
- Arachidonic acid and prostaglandins have many effects
- Gastro-intestinal adverse effects of chronic aspirin
- Stomach bleeding
- Ulcers
- Gastro-intestinal adverse effects of chronic aspirin
26
Q
Testosterone has anabolic & androgenic effects
- Anabolic effects of testosterone:
- … protein synthesis
- … catabolism (by opposing cortisol & glucocorticoids)
- … fat: increase BMR, increase differentiation to muscle (rather than fat cells)
- Anabolic steroid abuse
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- male – testes atrophy, sterility, baldness
- female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
A
- Anabolic effects of testosterone:
- Increases protein synthesis
- Decreases catabolism (by opposing cortisol & glucocorticoids)
- Reduces fat: increase BMR, increase differentiation to muscle (rather than fat cells)
- Anabolic steroid abuse
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- male – testes atrophy, sterility, baldness
- female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
27
Q
Testosterone has anabolic & androgenic effects
- Anabolic effects of testosterone:
- Increases protein synthesis
- Decreases … (by opposing cortisol & glucocorticoids)
- Reduces …: increase …, increase differentiation to muscle (rather than … cells)
- Anabolic steroid …
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- male – testes atrophy, sterility, baldness
- female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
A
- Anabolic effects of testosterone:
- Increases protein synthesis
- Decreases catabolism (by opposing cortisol & glucocorticoids)
- Reduces fat: increase BMR, increase differentiation to muscle (rather than fat cells)
- Anabolic steroid abuse
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- male – testes atrophy, sterility, baldness
- female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
28
Q
Anabolic steroid abuse
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (…, liver, heart, … changes)
- Male – testes …, sterility, baldness
- Female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
A
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – testes atrophy, sterility, baldness
- Female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
29
Q
Anabolic steroid abuse
- Used to increase … size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – testes atrophy, sterility, baldness
- Female – breast/uterus atrophy, … changes, … hair, … of voice
A
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – testes atrophy, sterility, baldness
- Female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
30
Q
Anabolic steroid abuse
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – … atrophy, sterility, baldness
- Female – …/… atrophy, menstrual changes, facial hair, deepening of voice
A
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – testes atrophy, sterility, baldness
- Female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
31
Q
Anabolic steroid abuse
- Used to increase muscle size and strength
- … … required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – testes atrophy, s…, b…
- Female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
A
- Used to increase muscle size and strength
- Large doses required – leads to damaging side effects (kidney, liver, heart, mood changes)
- Male – testes atrophy, sterility, baldness
- Female – breast/uterus atrophy, menstrual changes, facial hair, deepening of voice
32
Q
Effect of spaceflight
- Exposed to … … (long-term exposure)
- … in weight bearing in bones and muscles, over time, transition of Type 1 (slow) fibres to Type IIA/IIX fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
A
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type 1 (slow) fibres to Type IIA/IIX fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
33
Q
Effect of spaceflight
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type … (slow) fibres to Type …fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
A
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type 1 (slow) fibres to Type IIA/IIX fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
34
Q
Effect of spaceflight
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type 1 (…) fibres to Type IIA/IIX fibres (… fibres)
- Lose … fibres, gain … fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
A
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type 1 (slow) fibres to Type IIA/IIX fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
35
Q
Effect of spaceflight
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type 1 (slow) fibres to Type IIA/IIX fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in … … mass - all muscles undergo some …, but predominantly … bearing muscles
A
- Exposed to zero gravity (long-term exposure)
- Decrease in weight bearing in bones and muscles, over time, transition of Type 1 (slow) fibres to Type IIA/IIX fibres (Faster fibres)
- Lose slow fibres, gain fast fibres
- Decrease in relative muscle mass - all muscles undergo some atrophy, but predominantly weight bearing muscles
36
Q
Effect of bed-rest
- Muscles of posture are not being consistently used
- Transition of type … fibres to type …
- Weight-bearing muscle …
- Decrease muscle protein synthesis
- Myofibrillar breakdown
- Decreased strength (due to ¯ size)
- Loss of type … fibres
- Treat by resuming minor activity early, Add physiotherapy to prevent contractures.
A
- Muscles of posture are not being consistently used
- Transition of type I fibres to type IIA
- Weight-bearing muscle atrophy
- Decrease muscle protein synthesis
- Myofibrillar breakdown
- Decreased strength (due to ¯ size)
- Loss of type I fibres
- Treat by resuming minor activity early, Add physiotherapy to prevent contractures.
37
Q
Effect of bed-rest
- Muscles of posture are not being consistently used
- Transition of type I fibres to type IIA
- Weight-bearing muscle atrophy
- Decrease muscle protein …
- … breakdown
- Decreased … (due to ¯ size)
- Loss of type … fibres
- Treat by resuming minor activity early, Add physiotherapy to prevent contractures.
A
- Muscles of posture are not being consistently used
- Transition of type I fibres to type IIA
- Weight-bearing muscle atrophy
- Decrease muscle protein synthesis
- Myofibrillar breakdown
- Decreased strength (due to ¯ size)
- Loss of type I fibres
- Treat by resuming minor activity early, Add physiotherapy to prevent contractures.
38
Q
Effect of bed-rest
- Muscles of posture are not being consistently used
- Transition of type I fibres to type IIA
- Weight-bearing muscle atrophy
- Decrease muscle protein synthesis
- Myofibrillar breakdown
- Decreased strength (due to ¯ size)
- Loss of type I fibres
- Treat by resuming minor activity early, Add … to prevent ….
A
- Muscles of posture are not being consistently used
- Transition of type I fibres to type IIA
- Weight-bearing muscle atrophy
- Decrease muscle protein synthesis
- Myofibrillar breakdown
- Decreased strength (due to ¯ size)
- Loss of type I fibres
- Treat by resuming minor activity early, Add physiotherapy to prevent contractures.
39
Q
Summary Fibre Types
A
Dont need to memorise
40
Q
Contracture
- If limb immobilised for long periods:
- Process of growth is …
- … are removed in series from myofibrils
- Resulting in … of muscle called a contracture
- Patients with paralysed limbs must have physical therapy to prevent contractures occurring
A
- If limb immobilised for long periods:
- Process of growth is reversed
-
Sarcomeres are removed in series from myofibrils
- Resulting in shortening of muscle called a contracture
- Patients with paralysed limbs must have physical therapy to prevent contractures occurring
41
Q
Contracture
- If limb immobilised for long periods:
- Process of growth is reversed
- Sarcomeres are removed in series from myofibrils
- Resulting in shortening of muscle called a contracture
- Patients with … limbs must have … … to prevent contractures occurring
A
- If limb immobilised for long periods:
- Process of growth is reversed
- Sarcomeres are removed in series from myofibrils
- Resulting in shortening of muscle called a contracture
- Patients with paralysed limbs must have physical therapy to prevent contractures occurring
42
Q
Skeletal muscle cells are multinucleate
- They develop as …
- Which are mononucleate
- Then the … fuse
- The … are peripheral
- The multinucleate cells do not divide
- Mitosis with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- Increased vascularisation
A
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are peripheral
- The multinucleate cells do not divide
- Mitosis with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- Increased vascularisation
43
Q
Skeletal muscle cells are multinucleate
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are peripheral
- The … cells do not divide
- … with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- Increased vascularisation
A
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are peripheral
- The multinucleate cells do not divide
- Mitosis with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- Increased vascularisation
44
Q
Skeletal muscle cells are multinucleate
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are peripheral
- The multinucleate cells do not divide
- Mitosis with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- … enlargement
- Increased …
A
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are peripheral
- The multinucleate cells do not divide
- Mitosis with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- Increased vascularisation
45
Q
Skeletal muscle cells are multinucleate
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are …
- The multinucleate cells do not divide
- Mitosis with … nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- … vascularisation
A
- They develop as myoblasts
- Which are mononucleate
- Then the myoblasts fuse
- The nuclei are peripheral
- The multinucleate cells do not divide
- Mitosis with multiple nuclei usually impossible
- Skeletal muscles are enlarged by:
- Fibre enlargement
- Increased vascularisation
46
Q
Muscle Regeneration
- During … and … of damaged muscle tissue
- previous quiescent myogenic cells, called satellite cells, are activated
- These proliferate, differentiate and fuse onto extant fibres
- They contribute to forming multinucleate myofibers
A
- During inflammation and degeneration of damaged muscle tissue
- previous quiescent myogenic cells, called satellite cells, are activated
- These proliferate, differentiate and fuse onto extant fibres
- They contribute to forming multinucleate myofibers
47
Q
Muscle Regeneration
- During inflammation and degeneration of damaged muscle tissue
- previous … myogenic cells, called … cells, are activated
- These proliferate, differentiate and fuse onto extant fibres
- They contribute to forming multinucleate myofibers
A
- During inflammation and degeneration of damaged muscle tissue
- previous quiescent myogenic cells, called satellite cells, are activated
- These proliferate, differentiate and fuse onto extant fibres
- They contribute to forming multinucleate myofibers
48
Q
Muscle Regeneration
- During inflammation and degeneration of damaged muscle tissue
- previous quiescent myogenic cells, called … cells, are activated
- These proliferate, differentiate and fuse onto … fibres
- They contribute to forming … myofibers
A
- During inflammation and degeneration of damaged muscle tissue
- previous quiescent myogenic cells, called satellite cells, are activated
- These proliferate, differentiate and fuse onto extant fibres
- They contribute to forming multinucleate myofibers
49
Q
Myosatellite cells
- … cells in muscle
- Also called “satellite cells”
- NOT related glial satellite cells
- Essential for … & …
- Most are quiescent
- Activated by mechanical strain
- Activation —> proliferation & differentiation
A
-
Progenitor cells in muscle
- Also called “satellite cells”
- NOT related glial satellite cells
- Essential for regeneration & growth
- Most are quiescent
- Activated by mechanical strain
- Activation —> proliferation & differentiation
50
Q
Myosatellite cells
- Progenitor cells in muscle
- Also called “satellite cells”
- NOT related glial satellite cells
- Essential for regeneration & growth
- Most are q…
- Activated by mechanical …
- Activation —> p… & d…
A
- Progenitor cells in muscle
- Also called “satellite cells”
- NOT related glial satellite cells
- Essential for regeneration & growth
- Most are quiescent
- Activated by mechanical strain
- Activation —> proliferation & differentiation
75
Q
Myoglobin: Diagnostic
- Myoglobin “ … O2”
- Protein + Haem group
- “… coloured”
- In plasma indicates … or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: ò serum K = cause of rhabdo,
- Increased K = result of rhabdo
A
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: ò serum K = cause of rhabdo,
- Increased K = result of rhabdo
76
Q
Myoglobin: Diagnostic
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to … failure
- … tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: ò serum K = cause of rhabdo,
- Increased K = result of rhabdo
A
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: ò serum K = cause of rhabdo,
- Increased K = result of rhabdo
77
Q
Myoglobin: Diagnostic
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: …
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: ò serum K = cause of rhabdo,
- Increased K = result of rhabdo
A
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: ò serum K = cause of rhabdo,
- Increased K = result of rhabdo
78
Q
Myoglobin: Diagnostic
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: decreased serum K = … of rhabdo,
- Increased K = … of rhabdo
A
- Myoglobin “ Buffers O2”
- Protein + Haem group
- “tea coloured”
- In plasma indicates rhabdomyolysis or MI
- Can lead to renal failure
- Urine tested for myoglobin
- Diagnostic: Hyperkalaemia
- When muscle cells lyse
- They release K+
- This increases serum K+
- Nb: decreasd serum K = cause of rhabdo,
- Increased K = result of rhabdo
79
Q
Myoglobin: Diagnostic
- Urine tested for myoglobin - what does the patient have?
A
- Rhabdomyolysis
85
Q
Myasthenia gravis - Features
- … depolarisation of muscle fibres
- many fibres do not reach …
- repeated stimulation -> neuromuscular …
- symptoms include ptosis, diplopia,
- with weakness in eyelid and extraocular muscles
- proximal muscle weakness
A
-
less depolarisation of muscle fibres
- many fibres do not reach threshold
- repeated stimulation -> neuromuscular fatigue
- symptoms include ptosis, diplopia,
- with weakness in eyelid and extraocular muscles
- proximal muscle weakness
86
Q
Myasthenia gravis - Features
- less depolarisation of muscle fibres
- many fibres do not reach threshold
- repeated stimulation -> neuromuscular fatigue
- symptoms include p.., d…
- with … in eyelid and extraocular muscles
- proximal muscle …
A
- less depolarisation of muscle fibres
- many fibres do not reach threshold
- repeated stimulation -> neuromuscular fatigue
- symptoms include ptosis, diplopia,
- with weakness in eyelid and extraocular muscles
- proximal muscle weakness
96
Q
Fibre Type Grouping
- During … … atrophy
- Cycles of … are followed by collateral …
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in clusters (Figure B)
A
- During spinal muscular atrophy
- Cycles of denervation are followed by collateral reinnervation
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in clusters (Figure B)
97
Q
Fibre Type Grouping
- During spinal muscular …
- … of denervation are followed by collateral reinnervation
- Surviving axons … surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in clusters (Figure B)
A
- During spinal muscular atrophy
- Cycles of denervation are followed by collateral reinnervation
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in clusters (Figure B)
98
Q
Fibre Type Grouping
- During spinal muscular atrophy
- Cycles of denervation are followed by collateral reinnervation
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are …. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in … (Figure B)
A
- During spinal muscular atrophy
- Cycles of denervation are followed by collateral reinnervation
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in clusters (Figure B)
99
Q
Fibre Type Grouping
- During … muscular atrophy
- Cycles of denervation are followed by collateral reinnervation
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons …-… the … fibres, resulting in clusters (Figure B)
A
- During spinal muscular atrophy
- Cycles of denervation are followed by collateral reinnervation
- Surviving axons innervate surrounding fibres
- Resulting in fibre type grouping
- In healthy muscles (Figure A), motor units are intermingled. During reinnervation, nearby surviving neurons re-innervate the denervated fibres, resulting in clusters (Figure B)
112
Q
Muscular dystrophies
- Group of … disorders
- Severe and progressive … of muscle
- Muscle weakness
- Due to myopathy, not neuropathy
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
A
- Group of inherited disorders
- Severe and progressive wasting of muscle
- Muscle weakness
- Due to myopathy, not neuropathy
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
113
Q
Muscular dystrophies
- Group of inherited disorders
- Severe and progressive wasting of muscle
- Muscle …
- Due to …, not …
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
A
- Group of inherited disorders
- Severe and progressive wasting of muscle
- Muscle weakness
- Due to myopathy, not neuropathy
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
114
Q
Muscular dystrophies
- Group of inherited disorders
- Severe and progressive wasting of muscle
- Muscle weakness
- Due to myopathy, not neuropathy
- … gate
- C…
- … muscle involvement
A
- Group of inherited disorders
- Severe and progressive wasting of muscle
- Muscle weakness
- Due to myopathy, not neuropathy
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
115
Q
Muscular dystrophies
- Group of inherited disorders
- … and … wasting of muscle
- Muscle weakness
- Due to …, not neuropathy
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
A
- Group of inherited disorders
-
Severe and progressive wasting of muscle
- Muscle weakness
- Due to myopathy, not neuropathy
- Waddling gate
- Contractures
- Cardiorespiratory muscle involvement
116
Q
Duchenne muscular dystrophy
- …-linked disease
- affects 1:3500 live … births
- one third of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by fibrofatty connective tissue
- Mutation: gene for dystrophin protein
A
- x-linked disease
- affects 1:3500 live male births
- one third of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by fibrofatty connective tissue
- Mutation: gene for dystrophin protein
117
Q
Duchenne muscular dystrophy
- x-linked disease
- affects 1:… live male births
- one third of cases arise spontaneously
- … loss of muscle tissue
- replaced by fibrofatty connective tissue
- Mutation: gene for dystrophin protein
A
- x-linked disease
- affects 1:3500 live male births
- one third of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by fibrofatty connective tissue
- Mutation: gene for dystrophin protein
118
Q
Duchenne muscular dystrophy
- x-linked disease
- affects 1:3500 live male births
- one third of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by … connective tissue
- Mutation: gene for … protein
A
- x-linked disease
- affects 1:3500 live male births
- one third of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by fibrofatty connective tissue
- Mutation: gene for dystrophin protein
119
Q
Duchenne muscular dystrophy
- x-linked disease
- affects 1:3500 live male births
- one … of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by fibrofatty … tissue
- Mutation: gene for dystrophin protein
A
- x-linked disease
- affects 1:3500 live male births
- •one third of cases arise spontaneously
- progressive loss of muscle tissue
- replaced by fibrofatty connective tissue
- Mutation: gene for dystrophin protein
120
Q
…’ sign is a medical sign that indicates weakness of hip and thigh muscles associated with muscular dystrophy. The patient that has to use his hands and arms to “walk” up his own body from a squatting position.
A
Gowers’ sign is a medical sign that indicates weakness of hip and thigh muscles associated with muscular dystrophy. The patient that has to use his hands and arms to “walk” up his own body from a squatting position.
121
Q
Gower’s sign is a medical sign that indicates weakness of hip and thigh muscles associated with … … The patient that has to use his hands and arms to “walk” up his own body from a squatting position.
A
Gowers’ sign is a medical sign that indicates weakness of hip and thigh muscles associated with muscular dystrophy. The patient that has to use his hands and arms to “walk” up his own body from a squatting position.
