Pressure is low Pressure of atria is higher than ventricles c AV valves open

Pressure is low pressure of atria is higher than

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Pressure is low (Pressure of atria is higher than ventricles)c.AV valves open while SV valves are closedd.After 70% of ventricular filling, the AV valves begin to closei.Results in P wave and atrial systolee.Atrial pressure increases and final 30% of blood enters ventricle (EDV) resulting in atrial diastole for the rest of the cardiac cyclei.EDV is End Diastolic Volume2.Ventricular Systole a.Comprises of QRS complexes and T wavesb.Ventricles begin to contract causing an increased pressure which closes AV valvesc.There is a period of Isovolumetric Contraction (The volume is constant and it’s a closed system)i.This causes an increased pressure which opens SL valves resulting in Ventricular Ejection Phase(Aortic pressure goes up to 120mmHg)3.Isovolumetric Relaxationa.Early Diastole(Ventricles relax)b.Pressure decreases rapidly and there is backflow of aortic/pulmonary blood which closes SL valves (Dicrotic Notch)
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c.Ventricles in a closed system is called Isovolumetric Relaxation4.Back to Period of Ventricular Fillinga.Atria continued in diastole and have been fillingb.When Atria pressure is greater than ventricular pressure, AV valves open and it goes back to ventricular fillingFeatures during Cardiac Cycle-Blood flow through heart is controlled entirely by pressure changes-Blood flows from higher to lower pressure through any available opening-Electrical activity of left and right hearts is almost simultaneousThere are 2 distinguishable sounds that can be heard through a stethoscope-1stHeart Soundwhich is the closure of AV valves (The beginning of systole)-2ndHeart Soundwhich is the closure of Semilunar valves (The end of systole)-Heart sounds is due to vibrations of heart/chest due to valve closureHeart Murmurs-Due to Valvular ObstructionoHigh velocity jet of blood through narrow opening (Causes higher pitch of sounds)-Due to Valvular InsufficiencyoLeakage of blood back causes sounds when there should be silenceThe contraction of ventricles is referred to as Systoleand the period of ventricular relaxation is called
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Diastole. The first heart sound is a result of closure of the Atrioventicular Valveand closure of the Semilunar Valvecauses the second heart sound. The heart chambers that have just been filled when you hear the first heart sound are the Ventricles. The chambers that have just emptied when you hearthe first heart sound are the Atria. Immediately after the second heart sound, the Atriaare filling and the Ventricleshave emptied. Abnormal sounds (Murmurs) usually indicate valve problems.Cardiac Output-The amount of blood pumped from left ventricle into aorta per minute-Average cardiac output for a resting healthy male is 5L/min-Equation CO = HR*SVoCO = Cardiac OutputoHR = Heart RateoSV = Stroke VolumeSV = EDV – ESV EDV = End Diastolic VolumeESV = End Systolic VolumeInfluences of Exercise on Heart Rate and Stroke Volume-Cardiac output is 4-5 times higher in a fit person and 7 times higher in a marathon runner-There is a notion of Cardiac Reserve-Exercise has combined effects on Heart Rate and Stroke Volume
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