Energy Metabolism in Muscle Flashcards Preview

MSS - MSK Exam 3 > Energy Metabolism in Muscle > Flashcards

Flashcards in Energy Metabolism in Muscle Deck (46)
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1

main fuel in exercising muscles?

glycogen, glucose, free fatty acids

2

energy at rest?

predominantly fatty acids

3

high intensity isometric exercise energy?

anaerobic glycolysis and creatine kinase

4

submaximal exercise, low intensity?

blood glucose and free fatty acid

5

submaximal, high intensity?

more from glycogen and glucose
-glycogen main source

6

fatigue?

when glucose and glycogen stores are depleted

7

first hour of mild, low intensity?

glucose, glucagon and free fatty acids

8

one to four hours mild to moderate prolonged exercise?

free fatty acids increase substantially

**after four hours, free fatty acids main source

9

what maintains ATP levels?

glycogen and glucose metabolism
oxidative phosphorylation
creating kinase
purine nucleotide synthesis
lipid metabolism

10

anaerobic glycolysis

high intensity, isometric activity

results in fatigue - increasead lactate - acidification

11

aerobic glycolysis

dynamic isotonic exercise

pyruvate > acetyl CoA > TCA Cycle

12

rate limiting step in glycolysis?

fructose 6 P to fructose 1,6 BP
-enzyme: PFK

13

oxidative phosphorylation

18x more ATP than glycolysis alone

14

phosphocreatine pathway

enzyme: creatine kinase

phosphocreatine + ADP > ATP + creatine

duration of reaction is very small
-first 2-7 seconds

15

where is creatinephosphate synthesized?

liver and transported to muscle cells via bloodstream

16

location of creatine kinase?

skeletal muscle, heart, brain

17

CK 1

CK BB in brain, smooth muscles of lungs

18

CK 2

CK MB in heart

19

CK 3

CK MM in skeletal muscle

20

CK in blood tests?

elevation can indicate:
MI
rhabdomyolysis
muscular dystrophy
acute renal failure
drugs

21

purine nucleotide cycle

intensely exercising muscle can generate ATP over a short period using adenylate reaction

two ADP into ATP and AMP

22

fate of AMP

deaminated to IMP

enzyme: myoadenylate deaminase
-produced ammonia

higher in type 2 fast muscle fibers**

23

AMP deaminase?

AMP > IMP

releases ammonia

24

exercise induced myopathy and most common cause of metabolic myopathy?

deficiency in AMP deaminase

25

beta oxidation

of fatty acids

at rest - main energy substrate for muscles

26

what fatty acids can cross membrane?

less than 10 carbons
-can cross inner and outer mito membranes
-undergo beta oxidation

27

what happens with long chain fatty acids?

cannot cross mito membrane

activated by long chain acyl CoA synthetase
-to CoA thioester which crosses outer membrane

28

palmitoylcarnitine

transferred across inner mito membrane

-carnitine:acylcarnitine translocase

converted back to free acyl-CoA and carntine
-enzyme: CPT II

29

CPT I

combines acyl-CoA with carnitine

acylcarnitine can then be transferred across inner membrane

30

how does acylcarnitine get across inner membrane?

carnitine:acylcarnitine translocase

converted back to acyl-CoA (carnitine recycled outside)

acyl-CoA then is beta-oxidized