Exam 1 Flashcards
macromolecules for aerobic metabolism
carbs
fatty acids
proteins
macromolecules for anaerobic metabolism
carbohydrates
only significant foods that can be used to provide energy without utilization of 02 is:
carbohydrates
ATP-PCr system
- phosphocreatine is 3-8x more abundant
- cannot be used directly for cellular work
- acts as a buffer system for ATP
- replenishes ATP during exercise
ATP-PCr system is catalyzed by
creatine kinase
ATP-PCr system can generate ATP for how long?
15 sec
glycolytic system
- uses glucose or glycogen as its substrate
- occurs with or without oxygen
glycolytic system can generate ATP for how long?
2 min
ATP yield from glycolytic system
- 2 ATP for glucose
- 3 ATP for glycogen
cons of glycolytic system
- low ATP yield, inefficent use of substrate
- lack of 02 converts pyruvic acid to lactic acid
- lactic acid impairs glycolysis, muscle contraction
pros of glycolytic system
- allows muscles to contract when 02 limited
- permits shorter term, higher intensity exercise than oxidative metabolism can sustain
high energy demands during exercise comes from:
anaerobic sources:
- ATP present in muscle cells
- Phosphocreatine stores
- glycolytic breakdown of glycogen into lactic acid
ATP yield from oxidative system:
- 32 to 33 ATP per 1 glucose
- 100+ ATP per 1 FFA
Oxidative system
- occurs in the mitochondria
- takes hours to days
- includes the Krebs cycle and electron transport chain
oxidation of fat
- triglycerides: major fat energy source
- rate of FFA entry into muscle depends on concentration gradient
- yields 3 to 4 times more ATP than glucose
- slower than glucose oxidation
beta-oxidation of fat
- process of converting FFAs to acetyl-CoA before entering Krebs cycle
- requires up-front expenditure of 2 ATP
- fat oxidation require more 02 now, but yields far more ATP later
oxidation of protein
- rarely used
- can be converted to glucose, acetyl-CoA, or as intermediate in the Krebs cycle
hormones of absorption
insulin
growth hormone
hormones of postabsorption
- glucagon
- epinephrine
- norephinephrine
- cortisol
- growth hormone
stimulants of insulin release:
- increase in plasma glucose
- increase in plasma amino acids
- GIP secretion
- parasympathetic activity
insulin release is decreased with increased:
- sympathetic activity
- epinephrine secretion
how insulin effects most tissues:
- increase glucose uptake
- amino acid uptake
- increase protein synthesis
- decreased protein breakdown
how insulin effects adipose tissue
- increased fatty acid and triglyceride synthesis
- decreases lipolysis
how insulin effects liver and muscle
increases glycogen synthesis
-decreases glycogenolysis
how insulin effects the liver
- increases fatty acid and triglyceride synthesis
- decreases gluconeogenesis
normal blood glucose
70-100 mg/dL
hyperglycemia
glucose greater than 140 mg/dL
hypoglycemia
glucose less than 60 mg/dL
glucagon is secreted by which cells?
alpha cells
effect of glucagon on thee liver
-increases glycogenolysis
-decreases glycogen synthesis
-increases gluconeogensis
-increase ketone synthesis
-increase protein breakdown
decrease protein synthesis
effect of glucagon on adipose tissue
- increases lipolysis
- decreases triglyceride synthesis
effect of increased plasma glucose:
increase insulin
decrease glucagon
effect of increased plasma amino acids
increase both insulin and glucagon
effect of increased plasma GIP
increase insulin and glucagon
effect of increased parasympathetic activity
increased insulin decreased glucagon
effect of increased sympathetic activity
decrease insulin
increase glucagon
effect of increased plasma epinephrine
decrease insulin
increase glucagon
respiratory exchange ratio
- ratio between CO2 released and oxygen consumed
- tells us which substrate is being used
RER at rest (fasted)
0.78 to 0.80
RER oxidation of fat
0.70
RER oxidation of carbohydrate
1.0
endogenous energy sources:
- reside inside the tissue
- provide a readily available energy source
what substrates are used first at the beginning of exercise?
endogenous substrates
systems that are major energy contributors during the early minutes of high-intensity exercise:
ATP-PCr system
Glycolytic system
(lack of oxygen)
what substrate is used at the beginning of exercise?
intramuscular carbohydrates (as time goes on more fat metabolism
with an increase of parasympathetic activity then glucagon release is:
decreased
1 MET=
- 5 mL oxygen/ kg body weight/ min.
- oxygen required to sustain metabolism at rest
resting metabolic rate varies in proportion to:
- body’s surface area
- body mass
- lean body mass
% of daily energy usage:
60% basal metabolic rate
25% purposeful physical activity
7% nonexercise activity
8% thermic effect of food
factors that raise BMR
- lean body mass
- thyroid hormone, growth hormone, testosterone
- sympathetic system (increase cell activity; brown fat)
- fever
- cold climate/thermal regulation
- small body size
Effect of triiodothyronine on tissue:
T3
- increase BMR
- increase heat production
- increase responsiveness to sympathetic input
- permits normal growth and development
effect of T4/T3 on brain
facilitte activity of sympathetic nervous system by stimulating synthesis of beta receptors
average fat content in mature women
25%
average fat content in mature men
15%
Alpha cells of the pancreas secrete:
glucagon to increase blood glucose
beta cells of the pancreas secrete:
insulin to decrease blood glucose
delta cells of the pancreas secrete:
somatostatin(inhibits growth hormone) to inhibit glucagon
cells that are part of the exocrine function of the pancreas:
acinar cells
- secrete digestive enzymes
- mainly tripsinogen
processing of insuling:
- preproinsulin
- proinsulin
- insulin and C peptide
- insulin and C peptide packaged into secretory granulations
- insulin circulates unbound and can be removed from plasma by unsulinase
people with type II diabetes secrete more:
proinsulin
effects of insulin within seconds:
- increased glucose uptake by cells
- cell membranes more permeable to AAs and K+ and phosphate ions
effects of insulin within minutes:
- effects due to changing states of phosphorylatd enzymes
- ion channel movement
effects of insulin within hours to days:
-due to altered rates of translation of mRNA
protein synthesis
catecholamines use what mechanism for signaling?
cytoplasmic hormone receptors
