Lecture 5

Question 1

What are myokines?

Answer 1

myokines are hormones released by muscles and can have an effect elsewhere.

Question 2

What are the effects of insulin on the body?

Answer 2

Increases muscle glucose uptake
activates glycogen synthase
Inhibits liver glucose production
inhibits lipolysis

Question 3

What are the effects of glucagon on the body?

Answer 3

Stimulates glycogenolysis
Increases gluconeogenesis
Stimulates lipolysis

Question 4

What happens to insulin levels during exercise?

Answer 4

Plasma insulin levels fall progressively during exercise.

Question 5

What happens to glucagon levels during exercise?

Answer 5

Glucagon levels rise when glucose level falls during exercise.

Question 6

What causes decrease in insulin production during exercise?

Answer 6

Increase in sympathetic nervous system activity inhibits insulin production.

Question 7

What happens to insulin response if glucose is ingested during exercise?

Answer 7

Insulin is produced but the response is blunted.

Question 8

What happens to lipolysis during exercise if glucose is ingested?

Answer 8

ingesting carbohydrate during exercise inhibits lipolysis to a certain extent.

Question 9

What happens to glucagon if glucose is ingested during exercise?

Answer 9

Rise in glucagon is almost abolished when glucose is ingested during exercise.

Question 10

Interesting Fact

Answer 10

A single bout of exercise increases insulin sensitivity.

Question 11

How are the insulin and exercise pathway related? How does this cause increased insulin sensitivity?

Answer 11

Insulin intracellular pathway is fairly distinct from the exercise pathway with the result being GLUT4 synthesis. This increases insulin sensitivity because less insulin is needed to produce the needed amount of GLUT4.

Question 12

What happens to GLUT4 production when both insulin and exercise are introduced simultaneously?

Answer 12

Exercise and insulin responses are additive.

Question 13

Why do trained individuals have higher insulin sensitivity than untrained people?

Answer 13

Insulin signaling is cumulative with exercise signaling. (More GLUT4)
Hexokinase and glycogen synthase are more active.
Muscle oxidative capacity increased meaning more substrates are utilized.
More capillaries at muscles near mitochondria results in more substrates being used.

Question 14

What are the metabolic actions of adrenaline?

Answer 14

Increases glycogenolysis
Enhances liver glucose output
stimulates lipolysis

Question 15

How does increasing exercise intensity affect catecholamine levels?

Answer 15

norepinephrine at high intensities increases in blood stream. This is followed by increased epinephrine levels in the blood.

Question 16

What happens to adrenaline and noradrenaline levels during exercise?

Answer 16

adrenaline and noradrenaline increases with an increase in duration of exercise.

Question 17

What causes the increase in adrenaline levels during exercise?

Answer 17

dehydration, increase in temperature, fall in glucose

Question 18

What are the metabolic actions of cortisol?

Answer 18

Decrease in muscle glucose uptake
Increase muscle proteolysis
increases gluconeogenesis and liver glycogen synthesis
increases lipolysis

Question 19

What are the metabolic actions of HGH?

Answer 19

Increase IGF production
Decreased muscle glucose uptake
increased gluconeogenesis
Increased lipolysis
Increased amino acid uptake and protein synthesis.

Question 20

What affects cortisol levels?

Answer 20

Cortisol is released during times of stress
cortisol follows diurnal variations (variations throughout the day) this can have implications on athletes that travel overseas or interstate for their games.

Question 21

What system is involved in the feedforward response?

Answer 21

Feedforward response increases sympathoadrenal activity.