Between or after the lubb dupp or that may mask the

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between, or after the lubb-dupp or that may mask the normal sounds entirely. Not all murmurs are abnormal or symptomatic, but most indicate a valve disorder.
Heart Sounds
CardiodynamicsRefers to movements and forces generated during muscle contractions. End-diastolic volume (EDV):volume of blood in the ventricles at the end of ventricular diastole.End-systolic volume (ESV): volume of blood remaining in each ventricle at the end of ventricular systole. Stroke volume (SV): EDV – ESV
CARDIAC OUTPUTCardiac output(CO) is the volume of blood ejected from the left ventricle (or the right ventricle) into the aorta (or pulmonary trunk) each minute.Cardiac output equals the stroke volume(the volume of blood ejected by the ventricle with each contraction) multiplied by the heart rate(the number of beats per minute). CO = SV X HRat 70ml stroke volume & 75 beat/min----5 and 1/4 liters/minentire blood supply passes through circulatory system every minuteCardiac reserveis the ratio between the maximum cardiac output a person can achieve and the cardiac output at rest.average is 4-5x while athlete’s is 7-8x
Factors Affecting Cardiac OutputCardiac outputAdjusted by changes in heart rate or stroke volumeHeart rateAdjusted by autonomic nervous system or hormonesStroke volumeAdjusted by changing EDV or ESV
Regulation of Heart RateSeveral Factors affect heart rateIntrinsic regulation: Results from normal functional characteristics, not on neural or hormonal regulationExtrinsic regulation: Involves neural and hormonal controlParasympathetic stimulationSupplied by vagusnerve, decreasesheart rate, acetylcholineis secreted and hyperpolarizes the heartCan decrease the heart rate to 20-30 bpm.Sympathetic stimulationSupplied by cardiacnerves. Innervate the SA and AV nodes, coronary vessels and the atrial and ventricular myocardium. Increasesheart rate and force of contraction. Epinephrineand norepinephrinereleased.Can increase the heart rate to as high as 250-300 bpm.
Regulation of Heart Rate (Contd)Hormonal Control. Epinephrine and norepinephrine from the adrenal medulla. Occurs in response to increased physical activity. Cations (Na+, K+, Ca+2) also affect heart rate.age, gender, physical fitness, and temperature, emotional excitement, stress.
Factors affecting Stroke VolumeStroke volume is measured as the difference between end diastolic volume and end systolic volume. Therefore any changes in either EDV or ESV will have an impact on stroke volume. Some of these factors that impact stroke volume are:
Factors affecting Stroke VolumeEDV: is the amount of blood in a ventricle after diastole. Two factors influence this volume:Filling time: is the duration of the ventricular diastole, which is entirely dependent on heart rate.Venous return: varies in response to changes in cardiac output, blood volume, patterns of peripheral circulation etc. Preload:the degree of stretch in the heart before it contracts. Greater the preload on fibers just before

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