Muscle Metabolism- Sprint and Distance Flashcards Preview

Human Function- Exam 4 Material > Muscle Metabolism- Sprint and Distance > Flashcards

Flashcards in Muscle Metabolism- Sprint and Distance Deck (28):
1

what can muscle use as fuel?

anaerobic or aerobic metabolism
- creatine phosphate
-glucose
- muscle glycogen

aerobic metabolism only
-fatty acids
-ketone bodies
- amino acids

2

where does AMP come from in muscles?

combination of 2 ADP by adenylate kinase- makes an ATP and an AMP

3

what does AMP do?

allosterically activates phosphofructokinase-1 to stimulate glycolysis

4

what does phosphofructokinase-1 do?

stimulates muscle phophorylase b kinase- activates glycogen phosphorylase to break down glycogen

5

when is epinephrine released?

intense exercise

6

what does epinephrine do?

binds beta adrenergic receptors and activates the cAMP/PKA pathway which phospohrylates phosphorylase b kinase, which activates glycogen phophorylase

7

is muscle responsive to glycogen?

no
only epinephrine

8

what 3 things activate muscle glycogenolysis?

AMP
epinephrine
Ca

9

how do nerves stimulate muscle glycogenolysis?

increase cytoplasmic Ca which stimulates glycogen phophorylase b kinase (activates glycogen phosphoylase)

10

what source of energy is used in sprinting?

anaerobic metabolism of muscle only energy supply

11

what are the sources of ATP in sprinting muscle? how long do they last?

ATP pool- 1 sec
creatine-phosphoate pool- 4 sec
glycogen

12

why are fatty acids and ketone bodies not used in sprinting?

not enough time for them to diffuse into tissues
limited perfusion prevents diffusion anyway

13

what is the basis of fatigue when sprinting?

decreased pH
-limits force of contractions
-inhibition of PFK1 which decreases rate of glycolysis

14

what may combat fatigue onset in sprinting?

dietarty creatine and NaHCO3

15

what is the source of energy during prolonged exercise?

aerobic metabolism of muscle glycogen, glucose, fatty acids/ketone bodies (60%)

16

what type of fibers are primarily found in sprinters?

white fibers- few mitochondria

17

what type of fibers are primarily found in endurance athletes?

red fibers- lots of mitochondria

18

what processes are activated by epinephrine?

muscle glycogenolysis
liver glycogenolysis
TAG lipolysis

19

what processes are activated by glucagon?

liver glycogenolysis and gluconeogenesis
TAG lipolysis
NO effect on muscle

20

how is lactate production related to length of exercise?

decreases with increase duration because anaerobic glycolysis is decreased

21

what is the basis of fatigue in endurance exercise?

fuel and O2 depletion

22

what happens when glycogen is depleted?

major energy reduction
switch to fatty acid and blood glucose for energy source

23

what happens as prolonged exercise becomes more vigorous?

muscles get more hypoxic, switch to anaerobic metabolism
fatty acids aren't used as efficiently and muscle is more reliant on blood glucose (liver glycogenolysis and gluconeogenesis)

24

what are the current recommendations for carbohydrate loading prior to endurance events?

high carb diet during training
increase to 70% carbs and decreased training 2-3 days prior to event
results in 3 times more glycogen stores

25

what is the respiratory quotient?

ratio of CO2 exhaled to O2 consumed

26

how many CO2s are released during aerobic metabolism of glucose?

3- PDH, isocitrate dehydrogenase, and alpha ketogluterate dehydrogenase

27

how many CO2s are released when fatty acids are used?

2- skipped PDH step (isocitrate dehydrogenase and alpha ketogluterate dehydrogenase)

28

what happens to the RQ with increased exercise duration?

decrease because less CO2 is being produced when muscles switch from glycogen to fatty acids for energy