Lecture 5 Flashcards
What are myokines?
myokines are hormones released by muscles and can have an effect elsewhere.
What are the effects of insulin on the body?
Increases muscle glucose uptake
activates glycogen synthase
Inhibits liver glucose production
inhibits lipolysis
What are the effects of glucagon on the body?
Stimulates glycogenolysis
Increases gluconeogenesis
Stimulates lipolysis
What happens to insulin levels during exercise?
Plasma insulin levels fall progressively during exercise.
What happens to glucagon levels during exercise?
Glucagon levels rise when glucose level falls during exercise.
What causes decrease in insulin production during exercise?
Increase in sympathetic nervous system activity inhibits insulin production.
What happens to insulin response if glucose is ingested during exercise?
Insulin is produced but the response is blunted.
What happens to lipolysis during exercise if glucose is ingested?
ingesting carbohydrate during exercise inhibits lipolysis to a certain extent.
What happens to glucagon if glucose is ingested during exercise?
Rise in glucagon is almost abolished when glucose is ingested during exercise.
Interesting Fact
A single bout of exercise increases insulin sensitivity.
How are the insulin and exercise pathway related? How does this cause increased insulin sensitivity?
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.
What happens to GLUT4 production when both insulin and exercise are introduced simultaneously?
Exercise and insulin responses are additive.
Why do trained individuals have higher insulin sensitivity than untrained people?
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.
What are the metabolic actions of adrenaline?
Increases glycogenolysis
Enhances liver glucose output
stimulates lipolysis
How does increasing exercise intensity affect catecholamine levels?
norepinephrine at high intensities increases in blood stream. This is followed by increased epinephrine levels in the blood.
What happens to adrenaline and noradrenaline levels during exercise?
adrenaline and noradrenaline increases with an increase in duration of exercise.
What causes the increase in adrenaline levels during exercise?
dehydration, increase in temperature, fall in glucose
What are the metabolic actions of cortisol?
Decrease in muscle glucose uptake
Increase muscle proteolysis
increases gluconeogenesis and liver glycogen synthesis
increases lipolysis
What are the metabolic actions of HGH?
Increase IGF production Decreased muscle glucose uptake increased gluconeogenesis Increased lipolysis Increased amino acid uptake and protein synthesis.
What affects cortisol levels?
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.
What system is involved in the feedforward response?
Feedforward response increases sympathoadrenal activity.
