Fuel Sources For Muscle And Exercise Metabolism Flashcards
What do T-tubules do?
Transports action potential to sarcoplasmic reticulum
What is sarcomere?
Contractile unit of the muscle fiber
What does myoglobin do?
Transports oxygen
What does Interleukin - 6 do?
Cytokine that stimulates glycogen breakdown.
What is actin?
Thin myofilaments
What is lipolysis?
Metabolism of fat stores
What is ATPase?
An enzyme that breaks down ATP for energy
What is Myosin?
Thick myofilaments
What is the TCA cycle?
Aerobic metabolism that occurs in the mitochondrion.
What does Tropomyosin do?
Tropomyosin is a protein filament that blocks binding sites on actin.
______ muscle fibers have fast contractile speed capability within oxidative capacity that makes them moderately resistant to fatigue.
Type IIa
Muscle fibers are recruited by size and speed in the following order:
_____, then ______, and finally ______ when needed.
Type I
Type IIa
Type IIx
List the three primary sources of energy metabolism (modes of ATP resynthesis) in the order they occur based on activity duration.
PCr hydrolysis
Glycolysis
Oxidative phosphorylation (aerobic metabolism)
True or false:
PCr provides energy that is sufficient to feel short duration, high intensity exercise such as interval sprints.
True
True or false:
Hydrogen ions released during glycolysis lower the pH level in muscle, increasing enzyme activity.
False
List 4 sources of energy storage in the human body
Liver glycogen, muscle glycogen, blood glucose, fat, protein
Fat stores provide fuel at a rate that can maintain exercise intensity up to ____ VO2max
60%
Hormone Insulin:
Source: _______
Stimuli for activation:______
Actions:_______
Insulin:
Source: Pancreas
Stimuli for activation: rise in glucose and amino acids.
Actions: glucose and amino acids uptake, inhibits lipolysis and protein breakdown.
Hormone Epinephrine:
Source: _______
Stimuli for activation:______
Actions:_______
Epinephrine:
Source: medulla of adrenal glands & the ends of sympathetic nerve fibers
Stimuli for activation: stress and drop in blood glucose.
Actions: glycogen breakdown, lipolysis in adipose tissue.
Hormone Cortisol:
Source: _______
Stimuli for activation:______
Actions:_______
Cortisol:
Source: Adrenal cortex
Stimuli for activation: stress, hormone activators
Actions: stimulates protein breakdown and lipolysis.
Growth hormone:
Source: _______
Stimuli for activation:______
Actions:_______
Growth hormone:
Source: anterior pituitary gland
Stimuli for activation: stress
Actions: liver glycogen breakdown, lipolysis and adipose tissue, cortisol secretion.
True or false:
Glycogen depletion is the limiting factor for fatigue during prolonged, submaximal exercise?
True
List to muscular adaptations to aerobic training that improve endurance capacity.
A. Increased capillary density
B. increased mitochondrial size and quantity
C. increased activity of the TCA cycle and oxidative enzymes
D. increase capacity to use fat as an energy source, spares glycogen,
E. increased cross-sectional Area of Type I fibers
F. decreased lactate accumulation
G. increased cardiac output
H. VO2 Max and oxygen delivery to working muscle
I. attenuated stress hormone responses that delete glycogen.
Which of the following structures function to store calcium for use during muscular contractions?
A. Sarcomere
B. Myosin
C. Sarcoplasmic Reticulum
D. Myoglobin
C. Sarcoplasmic Reticulum
Type I muscle fibers do NOT present with which of the following characteristics?
A. Slow contraction right
B. Hi capacity for oxidative metabolism
C. Capability to perform repeated contractions for a long period of time.
D. Low capillary density
D. Low capillary density
Which of the following fiber types would be found in the highest proportion in a postural muscle such as the Soleus?
A. Type I fibers
B. Type IIa fibers
C. Type IIx fibers
D. Type III fibers
A. Type I fibers
Which of the following selections is the ultimate source of energy for all muscular work?
A. PCr
B. ATP
C. Glycogen
D. Fatty acid’s
B. ATP
Which of the following systems of metabolism involve the breakdown of carbohydrate without the presence of oxygen to fuel high intensity, shorter duration exercise?
A. B-oxidation
B. PCr hydrolysis
C. Glycolysis
D. Lipolysis
C. Glycolysis
Normal resting glycogen stores are usually depleted after which of the following durations of continuous intense exercise?
A. 30 - 45 minutes
B. 1 – 2 hours
C. 3.5 – 5.0 hours
D. Glycogen stores are rarely depleted.
B. 1 - 2 hours
Energy levels within muscle are regulated by each of the following except?
A. Enzymatic reactions
B. Sympathetic nervous system activity
C. Hormonal activity
D. Lactate synthesis
D. Lactate synthesis
Which of the following hormones stimulate liver glycogen breakdown and gluconeogenesis in response to a drop in blood glucose levels?
A. Insulin
B. Interleukin -6
C. Glucagon
D. Growth hormone
C. Glucagon
Which of the following is the primary cause of fatigue during high-intensity exercise lasting 1 to 5 minutes?
A. PCr depletion
B. Fat depletion
C. Hydrogen ion accumulation
D. Acetyl-coA accumulation
C. Hydrogen ion accumulation
Which of the following is NOT a muscular adaptation to aerobic training?
A. Increased mitochondrial size and quantity
B. Increased cross-sectional area of type I muscle fibers
C. Increased capacity to use fat as an energy source during submaximal efforts
D. Increased short-term glycolytic Energy delivery systems.
D. Increased short-term glycolytic Energy delivery systems.
