Lecture 22 - Skeletal muscle mass: mechanisms of hypertrophy Flashcards Preview

Muscle & Exercise Physiology > Lecture 22 - Skeletal muscle mass: mechanisms of hypertrophy > Flashcards

Flashcards in Lecture 22 - Skeletal muscle mass: mechanisms of hypertrophy Deck (21):
1

having an episode of acute major disease has a huge impact on...

exercise capacity in the years following

all daily activities will be completed at a higher intensity, more easily tired etc...

a downward spiral

2

How can you measure AAs in the body and work out if they are being oxidised?

continuous infusion of 13C-labelled AAs

measure the ratio of labelled/unlabelled in plasma

measure 13CO2/12CO2 ratio in breath

More 13CO2 in breath means more oxidation of infused tracer?

3

How is whole-body protein synthesis and breakdown measured?

constant infusion of labelled AA

measure plasma tracer enrichment against time

At a certain point the increase in labelled AA in the plasma will plataeu

The whole body protein metabolism can be determined from this (not sure if need to know the specifics)

4

The ____ contributes most to whole body protein turnover

muscle

despite the fact that other tissues, liver etc.. have a high synthesis rate

5

Protein synthesis and breakdown rates are not constant during the day, they are highly responsive to:

Food intake - protein, CHO, fat

Exercise

Inflammatory signals

hormones

6

With resistance exercise there is a __% increase in protein synthesis after exercise (3 hours)

100

remain elevated for 48 hours

7

True or false

mixed muscle protein synthesis is reduced during exercse

true

but increased for >24h post-exercise in untrained individuals

8

Resistance exercise increase ______ and _______ protein synthesis

myofibrilar and sarcoplasmic protein synthesis

9

true or false

Mitochondrial protenin synthesis rate

false, other way around

a

10

mitochondrial protein synthesis is favoured in ____ exercise

endurance

11

Exercise training alters the acute response to exercise

that different signalling pathways are activated

12

Increase muscle protein synthesis (MPS) could be achieved through which two means?

Increasing transcription of mRNA which in turn will lead to protein synthesis

or modify existing mRNA and influence at the translational level

13

True or False

Increased translation seems to drive increase MPS after exercise

ttrue

14

What are the signalling pathways that cause cell/tissue growth and proliferation?

P13K, mTOR, MAPKs

Also signal translation factors causing rapid activation of synthesis of specific proteins

15

Regulation of mTOR is very complex - just need to know that..

its one of the most important proteins in the regulation of protein synthesis

16

True of False

During exercise AMPK activity is decrease while mTOR signalling in increased

false

AMPK activity is increaed while mTOR signalling in decreased

AMPK shuts down alot of energy consuming proteins of wihch mTOR is one.

17

The effect of exercise on S6K1 is ________ specific.

Fibre type specific

18

If you block mTOR, what don't you get?

a metabolic response to exercise

19

What are the alterations in protein metabolism as we age?

initial hypothesis: basal protein synthesis is reduced and breakdown is increased

But this would account for a huge loss in muscle mass - its more like 8-10% per decade

Protein synthetic response to exercise is reduced in the elderly

Protein synthesis rates after physical activity and protein intake are significantly reduced in elderly humans

20

7 days of bed rest was shown to...

reduced the anabolic response to AA intake

21

What happens to protein synthesis in cancer patients?

the increase in protein synthesis after food intake is blunted

If the cancer is taken away the responses is restored

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