MOVESCI 340 QUESTIONS AND ANSWERS LATEST UPDATE
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Skeletal muscle comprises what percent of body mass?
40%
What is skeletal muscle essential for? (4)
posture, breathing, motion, and metabolic regulation
What is sarcopenia?
Loss of muscle strength and mass (age-related)
What are the adaptations involved in skeletal muscle?
increases in size/strength, mitochondrial increases, enzymatic increases, structural
integrity changes, among others
What is the thick and thin filaments of a sarcomere?
thick = myosin
thin = actin
How much ATP from the mitochondria goes to calcium and crossbridge cycling?
calcium cycling = 25%
crossbridge cycling = 75%
The majority of muscle is ...?
water
What are the components of the muscle at the tissue level?
water, intracellular protein, glycogen & IMTG, and extracellular protein
Why does it make sense that the skeletal muscle has glycogen and IMTG?
There is lots of glycogen and IMTG because these are the fuels to the skeletal muscle
What makes up the intracellular protein?
myofibrillar protein, sarco protein, and mito protein
What makes up the myofibrillar protein?
myosin (50%), actin (20%), nebulin/troponin/tropomyosin (20%), titin (10%)
What are satellite cells (their classification)?
muscle stem cells
Do skeletal muscle cells have one or many nuclei? Why?
Many -- nuclei are the source of protein (transcription), so more nuclei will supply these
long fiber cells with lots of protein
What is hypertrophy of skeletal muscle cells?
Increase in cross-sectional area (and a subsequent increase in nuclei)
Where are satellite cells found?
basal lamina
Why are satellite cells needed?
needed to repair and heal muscle in response to trauma or damage
What happens to the number of satellite cells with aging? What does this mean
for training adaptations?
decline in number; training adaptations take place more slowly (not the same as when
you are younger)
Satellite muscle cells play a role in ...
, the adaptation of muscle to aerobic and resistance training
Do myofibers typically replicate?
no
What will an activated satellite cell do? How do they become activated?
They can become activated (by trauma), and they add more nuclei, which will increase
the ability to produce more protein quickly.
What kind of trauma do satellite cells respond to?
resistance training or more extensive trauma (toxin injection, muscular dystrophy)
What is the purpose of satellite cells responding to trauma?
To make the fiber stronger for the next trauma incident
Skeletal muscle contains two main types of fibers that differ in...
- the primary mechanisms they use to produce ATP (metabolic)
- the type of motor neuron innervation (neural)
- the type of myosin heavy chain protein expressed (genetic/protein)
Why do the proportions of each type of muscle fiber vary from muscle to muscle
and from person to person?
genetics and training
What are the two main types of fibers?
Type I or red (slow) AND Type II or white (fast)
Are muscles normally all one fiber type or a mix of them?
mix of different fiber types
What are the three fiber types, their associated MHCs, and their biochemical
names?
Type I - MHCI - slow-oxidative
Type IIA - MHCIIa - fast-oxidative-glycolytic
Type IIX - MHCIIx - fast-glycolytic
What fiber type will have the fastest ATPase?
IIx
What does it mean for MHCs to be hybrid?
They are not purely type I, IIa, or IIx, but rather a mix of them
What is the ... of Fast Twitch fibers?
- contraction speed
- fiber size
- blood supply
- oxidative machinery
- oxidative or glycolytic?
- fatigue resistance?
- faster time to peak tension (around 20 ms)
- larger fibers (larger in diameter)
- smaller blood supply (less aerobic)
- fewer mitochondria, high content of glycolytic enzymes
- glycolytic
- fatigable
What is the ... of Slow Twitch fibers?
- contraction speed
- fiber size
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Skeletal muscle comprises what percent of body mass?
40%
What is skeletal muscle essential for? (4)
posture, breathing, motion, and metabolic regulation
What is sarcopenia?
Loss of muscle strength and mass (age-related)
What are the adaptations involved in skeletal muscle?
increases in size/strength, mitochondrial increases, enzymatic increases, structural
integrity changes, among others
What is the thick and thin filaments of a sarcomere?
thick = myosin
thin = actin
How much ATP from the mitochondria goes to calcium and crossbridge cycling?
calcium cycling = 25%
crossbridge cycling = 75%
The majority of muscle is ...?
water
What are the components of the muscle at the tissue level?
water, intracellular protein, glycogen & IMTG, and extracellular protein
Why does it make sense that the skeletal muscle has glycogen and IMTG?
There is lots of glycogen and IMTG because these are the fuels to the skeletal muscle
What makes up the intracellular protein?
myofibrillar protein, sarco protein, and mito protein
What makes up the myofibrillar protein?
myosin (50%), actin (20%), nebulin/troponin/tropomyosin (20%), titin (10%)
What are satellite cells (their classification)?
muscle stem cells
Do skeletal muscle cells have one or many nuclei? Why?
Many -- nuclei are the source of protein (transcription), so more nuclei will supply these
long fiber cells with lots of protein
What is hypertrophy of skeletal muscle cells?
Increase in cross-sectional area (and a subsequent increase in nuclei)
Where are satellite cells found?
basal lamina
Why are satellite cells needed?
needed to repair and heal muscle in response to trauma or damage
What happens to the number of satellite cells with aging? What does this mean
for training adaptations?
decline in number; training adaptations take place more slowly (not the same as when
you are younger)
Satellite muscle cells play a role in ...
, the adaptation of muscle to aerobic and resistance training
Do myofibers typically replicate?
no
What will an activated satellite cell do? How do they become activated?
They can become activated (by trauma), and they add more nuclei, which will increase
the ability to produce more protein quickly.
What kind of trauma do satellite cells respond to?
resistance training or more extensive trauma (toxin injection, muscular dystrophy)
What is the purpose of satellite cells responding to trauma?
To make the fiber stronger for the next trauma incident
Skeletal muscle contains two main types of fibers that differ in...
- the primary mechanisms they use to produce ATP (metabolic)
- the type of motor neuron innervation (neural)
- the type of myosin heavy chain protein expressed (genetic/protein)
Why do the proportions of each type of muscle fiber vary from muscle to muscle
and from person to person?
genetics and training
What are the two main types of fibers?
Type I or red (slow) AND Type II or white (fast)
Are muscles normally all one fiber type or a mix of them?
mix of different fiber types
What are the three fiber types, their associated MHCs, and their biochemical
names?
Type I - MHCI - slow-oxidative
Type IIA - MHCIIa - fast-oxidative-glycolytic
Type IIX - MHCIIx - fast-glycolytic
What fiber type will have the fastest ATPase?
IIx
What does it mean for MHCs to be hybrid?
They are not purely type I, IIa, or IIx, but rather a mix of them
What is the ... of Fast Twitch fibers?
- contraction speed
- fiber size
- blood supply
- oxidative machinery
- oxidative or glycolytic?
- fatigue resistance?
- faster time to peak tension (around 20 ms)
- larger fibers (larger in diameter)
- smaller blood supply (less aerobic)
- fewer mitochondria, high content of glycolytic enzymes
- glycolytic
- fatigable
What is the ... of Slow Twitch fibers?
- contraction speed
- fiber size
