LESSON 10 - hormonal control during exercise Flashcards
what are the four ways of substrate utilization during exercise ?
- muscle glycogen
- muscle triglycerides
- plasma Free Fatty Acids
- plasma glucose
“during exercise, a significant quantity metabolic substrate comes from ________ “
the blood
how do we maintain adequate levels of these substrate and regulate the delivery of these substrates ?
homeostasis
what is blood glucose homeostasis ?
ability to maintain blood glucose at resting levels
what are the two reasons maintenance of blood glucose levels during exercise is critically important ?
- glucose is a major substrate for metabolism
- glucose is the only fuel acceptable to the brain and other CNS tissues
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“a lot of the energy that our muscles cells / all the tissues in our body produce come from ________ “
glucose that is stored
what is our main energy source ?
glucose levels
what is the term given to those who cannot control their level of blood glucose very well ?
diabetic
why can CNS tissues only use glucose ?
glucose recevoir for the brain
what is normal resting blood glucose concentration in Canada ?
4.0 - 5.5 mol/L
what is normal resting blood glucose concentration in the US ?
90 - 100 mg/dL
does exercise increase or decrease glucose uptake from blood ?
increase
with every contraction what do we take more of ?
ATP
what initiated a cascade of signalling pathways that leads to the glucose uptake from blood ?
muscle contractions
what is the order of signalling pathways for glucose uptake ?
- contraction
- increase AMP, ATP ratio
- AMPK
- glut-4 vesicle
- glut-4 in plasma membrane
(goes either to blood vessel or ATP)
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“the more we overuse glucose, the more we ________ “
deplete
with every contraction what do we take more of ?
more ATP
where does insulin attach to glucose ?
glut-4 vesicle
when insulin attaches to glucose what receptor does it go to ?
glut-4 vesicle
what causes an increase in glut-4 vesicle transporters ?
exercise
what are glut-4 vesicles ?
transporters to the sarcolemma or plasma membrane of the muscle cells
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“glucose cannot enter the cell unless these ___________ for transporters are present on the plasma membrane “
glut-4 vesicles
TRUE OR FALSE
we store much glucose in our blood
FALSE
we do not store much glucose in our blood
can we rely on the glucose thats stored in the blood on its own ?
NO - we cannot rely on the glucose thats stores in the blood on its own to allow us to sustain any level of exercise or exercise intensity
what would happen if glucose stored in blood were the only fuel ?
(and its use was not immediately compensated for) blood glucose would fall rapidly
what happens to insulin as you exercise ?
- insulin drops as you exercise
- your body wants glucagon
a trick to know when glucagon is needed :
glucagon = glucose is gone
what does glucagon do?
when we do not have enough glucose it raises blood glucose levels
what is glucagon ?
hormone the breaks down glycogen
what is insulin ?
peptide hormone produced by beta cells in the pancreas
what does insulin do ?
takes glucose and stores it in the liver till your body needs it
what are the two ways we replenish blood glucose ?
glycogenolysis and glycogenesis
what is glycogenesis ?
production of new glucose molecules
what is glycogenolysis ?
breakdown of glycogen
what organ is a major player in the maintenance of glucose in the blood during exercise & the delivery of glucose to muscles during exercise ?
the liver
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increase release of glucose into the blood come from the ______, _____ and _______-
liver, gut and kidneys
what is hepatic glucose production ?
release of glucose from the liver
between gluconeogenesis and glycogenolysis, which is anabolic vs catabolic ?
gluconeogenesis = anabolic reactions
gycogenolysis = catabolic reactions
what are the two ways in which the liver can help maintain blood glucose from the liver ?
gluconeogenesis and gycogenolysis
between gluconeogenesis and gycogenolysis which has pyruvic acid and which glycogen ?
gluconeogenesis = pyruvic acid
gycogenolysis = glycogen
what are the steps of glycogenolysis ?
glycogen - >
< - glycogen phosphorylase
glucose 1 phosphate
< - phosphoglucomutase
G6P
becomes glucose
what are the steps of gluconeogenesis ?
( from lactic acid ) pyruvic acid - >
< - some amino acids (oxalic acid)
< - (from breakdown triglycerides) glycerol from lipids (DHAP)
G6P
becomes glucose
what is lipid mobilization ?
run out of glucose so you use triglycerides
where does lipid mobilization travel starting from adipose tissue and ending with the muscle ?
adipose tissue - blood plasma - muscle
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“thorough ______ we can release those free fatty acids into the blood”
lipolysis
triglycerides are how many kcal ?
50,000-100,000 kcal
what are the two pathways that triglycerides go to ?
FFA or glycerol
how do triglycerides travel through glycerol ?
- triglycerides in adipose tissue
- glycerol in blood plasma
-intramuscular triglyceride also to glycerol in blood plasma