Lecture 6 - CHO metabolism during exercise

Question 1

liver glucose output is subject to _____, _____ controls

Answer 1

multiple, redundant

Question 2

Training reduces reliance on ___ as a fuel source

Answer 2

CHO

Question 3

What converts Pyruvate to Lactate?

Answer 3

lactate dehydrogenase

Question 4

Early on in exercise the rate of glycogen breakdown is..

Answer 4

most rapid

Question 5

When glycogen runs out, this is associated with

Answer 5

exhaustion - assoicated with fatigue

Question 6

What are the factors that regulate glycogen breakdown?

Answer 6

Ca2+, Pi - the important local stimuli, will activate glycogen phosphorylase

Adrenaline - activates b receptors, stimulates glycogen breakdown

Muscle [glycogen] - offset slightly, but still advantageous to load muscle with glycogen = more of it

FFA - reciprocally increases/decreases

Temperature - direct effect of muscle temp - speeds up rate of reaction. Also supplies more adrenaline

Question 7

Trained individuals will reduce the amount of glycogen breakdown at a certain intensity because

Answer 7

there is less adrenaline

better regulation of your ATP turnover so the increase in Pi is not as high

Question 8

What are the determinants of glucose uptake into the muscle?

Answer 8

diffusion gradient

concentration in the capillaries

amount of GLUT 4 at the membrane

metabolism - hexokinase activity

Question 9

over time if the glucose concentration falls..

Answer 9

the glucose uptake is effected

Question 10

Glycogen in the muscle will reduce…

Answer 10

the glucose uptake (leaves it for the CNS)

Question 11

Adrenaline doesn’t necessarily influence glucose uptake, but does effect….

Answer 11

glycogen breakdown

Question 12

Liver glucose output is closely matched with…

Answer 12

muscle glucose uptake - but elongated exercise period cause liver glucose output to fall (there is a finite capacity)

Question 13

Is there glyocogen in the liver?

Answer 13

yes - broken down by _______

Question 14

Gluconeogenesis is mainly done in the …

Answer 14

liver, but also kidney and muscle

Question 15

an hour of exercise will drop liver glycogen levels by.

Answer 15

50%

Question 16

Glucagon will stimulate the enzymes involved in…

Answer 16

gluconeogenesis

Question 17

What are the factors which regulate liver glucose output during exercise?

Answer 17

feedforward and feedback mechanisms:

insulin (downreg.) and glucagon (from pancreas)

Adrenaline

Sympathetic nerves

Liver [glycogen] - if there’s more of it, more will be broken down (same as in muscle)

Blood [glucose] - when injested the endogenous glucose production is reduced - its already there from the GIT

Question 18

The liver is supplies by blood circulation from the…

Answer 18

Gut and pancreas

Question 19

After training there’s a reduction in _____ uptake and oxidation

Answer 19

glucose uptake and oxidation

Question 20

PDH activity goes down over time during exercise causing ..

Answer 20

a reduction of CHO oxidation - PDH a the rate limiting enzyme

Question 21

Liver glucose output is closely matched with Glucose ____

Answer 21

uptake

Question 22

What can be converted to glucose in the liver

Answer 22

AA, glycerol, Pyruvate, lactate

process called gluconeogenesis

Question 23

Does the muscle perform gluconeogenesis?

Answer 23

only a very small amount - during recovery

The kidney does a little but as well in the fasted state