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30 Cards in this Set
- Front
- Back
primary functions of the cardiovascular system during aerobic exercise? |
to deliver oxygen and other nutrients to the working muscles and remove metabolites and waste products |
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cardiac output |
the amount of blood pumped by the heart in liters per minute and is determined the quanitity of blood ejected with each beat (stroke volume) and the heart's rate of pumping (heart rate); Q=stroke volume x heart rate |
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stroke volume |
quantity of blood ejected with each beat; measured in milliliters of blood per beat; begins to increase at the onset of exercise and continues to rise until the individual's oxygen consumption is at approximately 40%-50% of maximal oxygen uptake, at this point SV begins to plateau |
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heart rate |
heart's rate of pumping; measured in beats (contractions) per minute |
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end-diastolic volume |
the volume of blood available to be pumped by the left ventricle at the end of the filling phase or diastole |
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two physiological mechanisms responsible for the regulation of stroke volume |
end-diastolic volume 2. the action of the catecholamines including epinephrine and norephinephrine, which are hormones of the sympathetic nervous system that produce a more forceful ventricular contraction and greater systolic emptying of the heart |
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venous return |
the amount of blood returning to the heart; increased during aerobic exercise due to a combination of venoconstriction (induced via increased sympathetic nervous system activation), the skeletal pump, and the respiratory pump (increased respiratory frequency and tidal volume) |
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frank-starling mechanism |
with an increased end-diastolic volume, the myocardial fibers become more stretched than at rest, resulting in more forceful contraction and an increase in force of systolic ejection and greater cardiac emptying; the concept that the force of contraction is a function of the length of the fibers of the muscle wall |
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ejection fraction |
a measurement of the percentage of blood that leaves the heart everytime it contracts |
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oxygen uptake |
the amount of oxygen consumed by the body's tissues |
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oxygen demand of working tissue is related to what? |
the mass of the exercising muscle, metabolite efficiency, and exercise intensity |
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maximal oxygen uptake |
the greatest amount of oxygen that can be used at the cellular level for the entire body |
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capacity to use oxygen is related primarily to what? |
the ability of the heart and circulatory system to transport oxygen and the ability of body tissues to use it. |
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what is resting oxygen uptake?
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3.5ml of oxygen per kilogram of body weight; this is also 1 metabolic equivalent (MET) |
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maximal oxygen uptake values in normal healthy individuals range from |
25-80 ml/kg/min or 7.1-22.9 METs |
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fick equation |
expresses the relationship of cardiac output, oxygen uptake, and arteriovenous oxygen difference; equation used to calculate oxygen uptake (VO2); VO2 = Q x a-vO2 difference |
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arteriovenous oxygen difference |
the difference in the oxygen content between arterial and venous blood); measured in milliters of oxygen per 100 ml of blood |
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how to calculate oxygen uptake |
VO2= heart rate x stroke volume x a-vO2 difference; you would then divide the result by the person's weight in kilograms |
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systolic blood pressure |
estimates the pressure exerted against the arteiral walls as blood is forcefully ejected during ventricular contraction (systole) and, when combined with heart rate, can be used to describe the myocardial oxygen consumption (work) of the heart |
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rate pressure product |
myocardial oxygen consumption (work) of the heart; rate-pressure product= heart rate x systolic blood pressure |
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diastolic blood pressure |
used to estimate the pressure exerted against the arterial walls when no blood is being forcefully ejected through the vessels (diastole); provides an indication of peripheral resistance and can decrease with aerobic exercise due to vasodilation |
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peripheral resistance |
the resistanc of the artieries to blood flow, as the artieries constrict, the resistance increases, and as they dilate, resistance decreases |
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vasodilation |
the dilation of blood vessels, which decreases blood pressure |
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systemic circulation |
the part of the CVS which carries oxygenated blood away from the heart to the body and returns deoxygenated blood back to the heart |
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mean arterial pressure |
the average blood pressure throughout the cardiac cycle; arterial pressure remains closer to diastolic pressure than systolic pressure so the mean arterial pressure is usaully less than the average of the systolic and diastolic pressures; mean arterial blood pressure =[(systolic blood pressure - diastolic blood pressure)/3] + diastolic blood pressure |
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average blood pressure with maximal aerobic exercise |
220-260 systolic and while diastolic remains at resting level or decreases slightly |
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primary mechanisms for regulating regional blood flow |
vasoconstriction and vasodilation |
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minute ventilation |
the volume of air breathed per minute; with aerobic exerise this increases as a result of increases in the depth of breathing, frequency of breathing, or both |
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tidal volume |
the amount of air inhaled and exhaled with each breath |
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ventilatory equivalent |
ratio of minute ventilation to oxygen uptake |