what does exercise require a steady supply of? and where does it come from?
ATP from metabolism or from conversion of phosphocreatine
characteristics of glycolytic metabolism?
2.5 times more rapid than aerobic pathways but not as efficient as ATP production
what influences glucose and fatty acid metabolism during exercise?
glucagon, cortisol, catecholamines, growth hormone (they favor the conversion of glycogen to glucose)
what is the significance of the rise in plasma glucose and decrease of insulin secretion during exercise?
glucose uptake by most cells is reduced, making more glucose available for exercising muscle
what indicates the intensity of exercise?
oxygen consumption (a person's maximal rate of oxygen consumption is an indicator of that persons ability to perform endurance exercise)
what is excess post exercise oxygen consumption due to?
ongoing metabolism, increased body temperature, circulating catecholamines
what is the limiting factor dealing with maximal exertion?
the ability of the cardiovascular system to deliver oxygen and nutrients
what does exercise hyperventilation result from?
feed forward signals from the motor cortex, and sensory feedback from peripheral sensory receptors (such as increased plasma K+ levels)
why does cardiac output increase with exercise?
because of increased venous return and sympathetic stimulation of heart rate and contractility
when does blood flow through exercising muscle increase dramatically?
when skeletal muscle arterioles dilate and arterioles in other tissues constrict
what acts as paracrines and cause local vasodilation?
decreased tissue O2 and glucose or increased muscle temperature, CO2 and acid
what can physical activity help prevent?
the risk of developing high blood pressure, strokes, and type 2 diabetes mellitus