Which of the following will NOT occur in response to an increase in sympathetic nervous activity?
D) increased insulin release
If a person starts exercising at a low intensity, a greater proportion of his or her energy will be generated from __________.
As the intensity of exercise increases, the relative contribution of _________ as an energy substrate is increased.
Which of the following statements about respiratory control during exercise is true?
E) all of these
The reduction in vasoconstriction within the vasculature of the skin during exercise in a hot environment is partly mediated by ________.
a decreased sensitivity of venous adrenergic receptors
What is true of energy mobilization during exercise?
- Increases in glucagon secretion mobilize energy stores.
- The liver releases glucose produced from glycogenolysis and gluconeogenesis into the bloodstream.
- Adipose tissue releases fatty acids into the blood stream.
Which of the following hormones is reduced during exercise?
The elevated plasma testosterone concentration in males leads to a _________ as compared with females.
greater rate of glycogenolysis
Elevated estrogen levels in females cause a higher rate of _________ during exercise.
The increase in plasma glucagon during exercise is caused by a(n) ____________.
increase in sympathetic nervous activity
During exercise, the baroreceptor reflex provides negative feedback control of heart rate _________?
when blood pressure has decreased due to fluid loss
Airway resistance is much higher at rest than during exercise, primarily due to an increased __________.
sympathetically-mediated bronchodilation during exercise
Even though gastrointestinal motility would be slowed during exercise by __________, the __________ during running would speed the movement of the contents.
increased sympathetic nervous activity; jarring movement
Which of the following would NOT stimulate the movement of digested food through the gastrointestinal tract?
A) hypo-osmotic beverage
During exercise in hot conditions, blood flow must be redistributed away from the ___________ to provide enough blood for active muscle.
Blood flow to what two organs is maintained at the expense of possible ischemia to other organs?
heart & brain
Changes in renal and splanchnic vascular resistance are proportional to ___________.
core body temperature
Sweat is a _________ solution whose loss would alter blood osmolarity in a direction that would _________ the production of ADH.
The fatigue associated with marathon running has been correlated with a _________.
depletion of glycogen
Name sources of the fatigue associated with elevated hydrogen ion concentration.
- inhibition of phosphofructokinase
- displacement of calcium ions from the troponin molecule
- interference with hormone-sensitive lipase
Name sources of muscle fatigue.
- phosphate-induced inhibition of phosphofructokinase
- calcium accumulation in the mitochondria
- potassium accumulation
- interference with mobilization of free fatty acids
The increase in urinary hydrogen excretion associated with exercise results from ______.
Depletion of glycogen from the slow-twitch fibers that are recruited first during exercise will lead to a(n) ___________ if exercise is to continue.
recruitment of fast-twitch fibers
Name sources of psychological fatigue.
- increase in blood hydrogen ion levels
The consequence of water and salt loss from sweating during long durations of exercise is ___________.
shrinkage of cells
Consumption of a large volume of deionized water following exercise can cause ________.
cells to swell
Water intoxication is associated with a(n) _________.
- decrease in osmolarity of extracellular fluid
- swelling of cells
What secretes proteins that serve antioxidative functions after exercise?
Tumor necrosis factor can cause _________.
- increased vascular permeability
- decreased cardiac contractility
Activity in the sympathetic nervous system before a bout of exercise helps to increase __________.
Ventilation changes during exercise are brought about by ________.
- negative feedback to prevent hyperventilation
- positive feedback due to central command
- positive feedback due to input from mechanoreceptors and chemoreceptors in exercising muscle
The ultimate limitations to aerobic exercise capacity may be due to ________.
the fixed size of the lungs
The plasma concentration of which of the following increases over the course of prolonged exercise?
So-called "runner's diarrhea" may be caused or exacerbated by __________.
ingestion of caffeine
Water is conserved during exercise due to increase in ________ secretion.
aldosterone, ADH, & renin
The fatigue that occurs during the later stages of intense exercise is due in part to depletion of __________ stores in muscle.
Which of the following increase in muscle cells during prolonged exercise, and may contribute to muscle fatigue?
When Bob replenished lost fluids with pure water, __________.
- his plasma became hypo-osmotic
- water moved into his cells to restore iso-osmotic conditions
- his cells swelled
Post-exercise fever is caused by the action of _________ on the thermoregulatory centers of the hypothalamus.
The sympathetically-mediated reduction in renal blood flow is counterbalanced by __________.
increased prostaglandin synthesis in the kidney & autoregulatory mechanisms that regulate blood flow