Hypertrophy and Satellite Cells

Question 1

________: muscle growth as _________: muscle loss

Answer 1

hypertrophy
atrophy

Question 2

what are some signals for anabolism (muscle growth)

Answer 2

• exercise (resistance> endurance)
• feeding
• growth factors and hormones

Question 3

what are some signals for catabolism (muscle loss)

Answer 3

• disuse atrophy
• starvation
• sarcopenia
• cachexia
• anorexia

Question 4

adaptations are ________ for the type of exercise

Answer 4

specific
“exercise specificity”

Question 5

primary adaptation to resistance exercise training is an increase in ________

Answer 5

a muscle’s force producing ability (strength)

Question 6

primary adaptation to endurance training is __________

Answer 6

metabolic efficiency

Question 7

increased muscle strength from resistance exercise is due to what two components?

Answer 7

neural and hypertrophy factors

Question 8

does neural or hypertrophic factors occur first?

Answer 8

neural

Question 9

early gains are due to _________ while long term gains are due to ________

Answer 9

alterations of neural control of trained muscle
increased muscle size (hypertrophy)

Question 10

in general muscle strength is ________ related to muscle size

Answer 10

directly

Question 11

primary muscle response to resistance exercise is muscle _________

Answer 11

hypertrophy

Question 12

what are 2 contributions to hypertrophy?

Answer 12

myofibrillar and sarcoplasmic hypertrophy

Question 13

what happens in myofibrillar hypertrophy

Answer 13

• increase in contractile proteins
• increase in number and size of myofibrils
• increase in connective, tendinous and ligamentous tissues

Question 14

what happens in sarcoplasmic hypertrophy

Answer 14

• increase in enzymes, stored nutrients, cytosol, and mitochondria

Question 15

T or F: you can lose myofibrillar elements faster than sarcoplasmic

Answer 15

F, you can lose sarcoplasmic adaptations much faster that myofibrillar

Question 16

T or F: type one skeletal muscle does not hypertrophy

Answer 16

F, it does, just type 2 fibers will show greater hypertrophy effects

Question 17

increase in muscle size is primarily from?

Answer 17

individual fibers getting larger

Question 18

larger number of CSA = increase number of __________

Answer 18

myofibrils

Question 19

when myofibrils reach a critical size they split __________

Answer 19

longitudinally

Question 20

RPS = RPD: ______ muscle
RPS > RPD: ______ muscle
RPS < RPD: _______ muscle

Answer 20

stable
increase/hypertrophy
decrease/atrophy

Question 21

resistance exercise will ________ protein synthesis

Answer 21

increase

Question 22

the larger the stimulus the ______ protein the body will create

Answer 22

more

Question 23

How does muscle protein increase? (the pathway)

Answer 23

DNA -> transcription -> mRNA -> translation at the ribosomes -> new proteins

Question 24

T or F: only RNA not DNA content increases during resistance exercise

Answer 24

F: DNA increases too because satellite cells merge with muscle cells

Question 25

what is the master regulator of protein synthesis?

Answer 25

mTORC1 regulation

Question 26

what are three types of overload stimuli that signals MTORC

Answer 26

1 - mechanotransduction
2 - signaling pathways
3 - gene regulation

Question 27

What are some inputs to the MTORC pathway?

Answer 27

growth factors (IGF, insulin)
energy status
O2 level
exercise
AA availability

Question 28

mTORC1 is _______ in the cytosol. with DEPTOR and PRAS40 are removed it becomes ________ at the lysosome

Answer 28

inactive
active

Question 29

what are outputs from the MTORC pathway

Answer 29

initiate RNA translation and protein synthesis
inhibit genes for lysosome biogenesis and autophagy

Question 30

T or F: you can have protein translation in a starved state with growth factors

Answer 30

F: you must be in a fed state WITH growth factors

Question 31

what are 3 jobs of satellite cells?

Answer 31

• proliferation (make daughter cells)
• self-renewal (make more of itself)
• differentiation (myoblasts)