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Terms in this set (95)

How long does the fed state last?
~3 hrs after a meal
What characterizes the fed state?
Insulin secretion
How long has it been since you ate when you're in the post-absorptive (between meals) state?
~3-18 hrs after a meal
What hormone rises during the post absorptive and fasting state?
Glucagon
How long has it been since you ate when you're in the fasting state?
18 hrs-2 days
How long has it been since you last ate in the starvation state?
Longer than 2 days
______ is the first tissue to use dietary glucose
Liver
Some glucose is retained in the liver, but ______ (amount) passes into systemic circulation
2/3
Retained glucose in the liver can enter __________ or be converted to _________
1) glycolysis
2)glycogen
Excess glucose (when glycogen storage is exceeded) can be converted to _________
1) fatty acids
_______ delivers fatty acids made from excessive glucose to the adipose for storage
1) VLDL
This process is a major provider of glucose to the blood in the post-absorptive state
Hepatic glycogenolysis
This process is important in maintaining blood glucose levels in the post-absorptive state
Gluconeogenesis
Both glycocenolysis and gluconeogenesis in the post-absorptive state are controlled by what hormone?
Glucagon
______ is a constant carbon source for hepatic gluconeogenesis
1) Lactate

**lactate is formed and released by red blood cells or formed by the skeletal muscle during anaerobic glycolysis
What are 2 factors for gluconeogenesis in the post-absorptive state?
1) Glucose-Alanine Cycle--alanine is converted to pyruvate in the liver (this cannot happen in the skeletal muscle)

2)Muscle glycogenolysis--provides glucose as fuel for muscles
Nearly all liver _____ is used up in the overnight fast
1) glycogen
What 3 things contribute to gluconeogenesis in the fasting state?
1) Amino acid break down from the muscle

2) Glycerol from lipolysis

3) Lactate from red blood cells or skeletal muscle

**AA break down is the primary contributor to gluconeogenesis in the fasting state
A high rate of breakdown from the muscle protein is accompanied by _______ losses through the urine
1) nitrogen
What is formed during the fasting state?
Ketones
What is glutamine's role during the fasting state?
Transporting and excreting amino acid nitrogen
During the starvation state, gluconeogenesis will shift to _______ in order to spare protein
1) lipolysis
During the starvation state, there will be an increase in these 3 things.
1) Increased use of fatty acids as fuel in certain tissues

2) Increased use of glycerol to make glucose through gluconeogenesis

3) Increased ketone body synthesis
Is lactate still used for gluconeogenesis in the starvation state?
Yes, red blood cells continually produce lactate from glycolysis under all metabolic conditions
What is the total production of glucose in humans during the starvation state?
~80 g/day
What happens when oxaloacetate stores are depleted during the starvation state?
Ketosis will occur
What do the kidneys do once ketosis occurs in the starvation state?
Produce ammonia to help neutralize acidity from ketone bodies
Survival time during starvation depends largely on what?
How much fat is stored in the specific individual
What hormone promotes anabolic reactions?
Insulin
What 3 hormones promote catabolic reactions?
-Glucagon
-Epinephrine
-Cortisol
What hormone promotes both anabolic and catabolic reactions depending on the tissue?
Growth hormone
What is the half-life of insulin?
4-6 minutes
Insulin is critical in the ____ state when large amounts of blood glucose must be removed to prevent hyperglycemia
1) fed
Insulin promotes the uptake of glucose into the muscle and adipose tissue by stimulating the translocation of ______
1) GLUT4
Insulin increases _____ synthesis in the skeletal muscle and liver, while inhibiting _______ in the liver
1) glycogen
2) gluconeogenesis
Insulin stimulates _____ synthesis
1) fatty acid
Glucagon is the prominent hormone in the ________ state
1) non-fed
Where is glucagon secreted from?
Alpha cells of pancreas
What is the half-life of glucagon?
3-6 minutes
Glucagon causes an increase of what 2 metabolic pathways in the liver?
1) Gluconeogenesis
2) Glycogenolysis
Glucagon increases _____ formation and _______
1) Ketone
2) lipolysis
Glucagon stimulates _______ in brown fat
1) thermogenesis
Where is epinephrine produced?
adrenal medulla
Epinephrine functions as a ________ in the nervous system and a _______ ______ in circulation
1)neurotransmitter
2) stress hormone
What is the half-life of epinephrine?
1-2 minutes
As a stress hormone, epinephrine can increase what 2 things?
1) cardiac muscle contractions
2) blood flow to the skeletal muscle and liver
Epinephrine is increased during _______
1) exercise
Epinephrine stimulates ______ in the skeletal muscle and liver
1) glycogenolysis
Epinephrine stimulates _____ in the skeletal muscle
1) glycolysis
Epinephrine stimulates _____ in adipose tissue an skeletal muscle
1) lipolysis
Epinephrine stimulates ______ secretion when bound to beta-receptors of the pancreas
1) glucagon
Where is cortisol produced?
adrenal cortex
Cortisol is released in response to what?
Low blood glucose levels
What is the half-life of cortisol?
~1 hr
Cortisol stimulates _______ and ________ in the liver
1)gluconeogenesis
2)glycogenolysis
Cortisol stimulates _______ in adipose tissue
1) lipolysis
What does cortisol inhibit?
The translocation of GLUT4 to the cell membrane
Does the amount and timing of nutrient intake influence health and performance outcomes?
Yes
Exercise increases circulating levels of what 3 hormones?
1) Epinephrine
2) Cortisol
3) Growth hormone
The circulating hormone levels that increase from exercise (epinephrine, cortisol, and growth hormone) increase what 3 metabolic pathways?
1) Gluconeogenesis
2)Glyogenolysis
3) Lipolysis

**this promotes release of more glucose and fatty acids into the bloodstream
Can fatty acids be used as an energy source when exercising?
Yes
What is VO2 max?
An individual's maximum rate of oxygen consumption
VO2 max ________ as a person trains more
1) increases
Skeletal muscle accounts for only _____ - ______ % of resting body energy use
20-25
Energy needs in the resting muscle are met primarily by _______ and _________ oxidation
1) fatty acid
2) glucose
3 energy systems that supply ATP during exercise
1) ATP-Phoshocreatine System
2) Lactic Acid System
3)Oxidative System
ATP-Phoshocreatine System provides energy in the ______ stage of exercise (within a few seconds)
1) early
ATP-Phoshocreatine System provides ________ to ADP to be regenerated to ATP
1) phosphate
How long does the ATP-Phoshocreatine System last during exercise?
15-25 seconds
How does the Lactic Acid System provide ATP to the body during exercise?
Phosphorylating one glucose molecule to 2 lactate molecules
How long does the Lactic Acid System last?
~20-75 seconds
What happens if blood lactate accumulates when the rate of production is greater than the rate of clearance?
Blood pH is lowered, causing fatigue
Why does the Oxidative System provide a lot more ATP compared to the other 2 systems?
Because this system involves the Electron Transport Chain
When does the Oxidative System occur?
When exercise exceeds 2-3 minutes
What does the skeletal muscle use as energy during light physical activity?
Fatty acids (primarily) and glucose

**will use amino acids as exercise conditions warrant
Why does the skeletal muscle primarily use fatty acids during exercise?
To conserve both blood glucose and muscle stores of glycogen and TAGs
What energy sources are used by the skeletal muscle at 60-75% VO2 max?
Fatty acids, stored glycogen, and TAGs
What occurs when the skeletal muscle is at 85% VO2 max?
Carbohydrate oxidation and degradation of glycogen begins

**Fatty acids will still be used as an energy source, but muscle glycogen will be primary fuel source at this stage of exercise
What causes muscle fatigue and what should you do to decrease it?
1) When the supply of glucose is inadequate

2) To decrease it, either reduce exercise or consume more glucose
What are the benefits of exercise training?
1) increased size and number of mitochondria

2) increased heart and lung capacity

3) increased use of fatty acids as energy source during moderate to intense training

4) muscle and plasma glycogen will deplete more slowly

5) increased capacity for muscle glycogen storage
Classical Regimen for Carb Loading
-2 sessions of intense exercise, 2 days of low carb diet (<10%), followed by 3 days of high carb diet (>90%) and rest
Side effects of classical regimen for carb loading
-dizziness
-irritation
-difficulty sticking to diet and exercise
Modified Regimen for Carb Loading
-Tapered exercise over 5 days followed by 1 day of rest

-3 days of 50% carbs in the diet, followed by 3 days of 70% carbs in the diet

-Achieved by consuming large quantities of pasta, rice, and bread
Benefits of modified regimen for carb loading
-can increase muscle glycogen stores by 20-40%

-fewer adverse side effects
Low glycogen approach for carb loading
-low carb diet to limit glycogen storage which promotes beta oxidation so fatty acids are used as fuel

-high carb diet will be consumed right before competition
Folate vs. Folic Acid
-Folate: reduced form found in foods and tissues

-Folic acid: oxidized form found in supplements or fortified foods
Sources of Folate
-leafy green vegetables
-legumes
-lentils
-beef liver
-some fruits and juices
Interaction of folate and B12
-adequate B12 is needed to form the correct forms of folate for DNA synthesis
How is folate excreted?
urine and feces
Recommended Dietary Allowance of Folate
-Adults: 400 µg DFE/day
-Pregnancy: 600 µg DFE/day
-Lactation: 500 µg DFE/day
Dietary Folate Equivalencies (DFE)
1 DFE = 1 µg of food folate
1 DFE = 0.6 µg of supplement with fortified folate
1 DFE = 0.5 µg of supplement without food
megaloblastic macrocytic anemia
-Results from folate deficiency

-number of red blood cells released into circulation is decreased, but they are immature and large in size
Functions of folate in amino acid and choline metabolism
Amino Acid metabolism:
-serine and glycine degradation
-histidine degradation
-Methionine and SAM synthesis

Choline metabolism:
-choline degradation
Functions of Folate in gene expression
folate can methylate DNA
Folate association with disease
-Folate deficiency can cause some cancers such as colon (main one), lung, and esophageal cancer

-Spina bifida
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