The Cardiac Cycle Flashcards
What happens during late diastole?
Late diastole = both sets of chambers are relaxed and ventricles fill passively.
What happens during atrial systole?
Atrial systole = atrial contraction forces a small amount of additional blood into ventricles.
What happens during isovolumic ventricular contraction?
First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves
What happens during ventricular ejection?
As ventricular pressure rises and exceeds pressure in the arteries, the semilunar valves open and blood is ejected
What happens during isovolumic ventricular relaxation?
As ventricles relax, pressure in ventricles falls, blood flows back into cusps of semilunar valves and snaps them closed
<p>What is happening at A, B, C and D</p>
<p>A - Mitral valve closes - Inital snap back of AV valve when pressure in the ventricle rises above pressure in the atrium</p>
<p>B - Aortic/ pulmonary/semi-lunar valve opens</p>
<p>C -Aortic/ pulmonary/semi-lunar valve closes</p>
<p>D - Mitral valve opens becuase pressure in the atrium is greater than that of the ventricle</p>
<p>What is the small rise in pressure between the aortic valve closing and the mitral valve opening because of?</p>
<p>It is known as the dicrotic notch, small bounce in pressure due to the aortic valve closing</p>
<p>What is A, B and C and typical values associated?</p>
<p>A - Systolic pressure - 120</p>
<p>B - Pulse pressure - 40</p>
<p>C - Diastolic pressure - 80</p>
<p>What is the mean arterial pressure?</p>
<p>Roughly diastolic plus one third of the pulse pressure</p>
<p>What is happening at stages A,B,C,D?</p>
<p>A - Rapid ejection</p>
<p>B - Slower ejection</p>
<p>C - Rapid filling</p>
<p>D - Slower filling</p>
<p></p>
<p>What is A, B and C?</p>
<p>End diastolic volume</p>
<p>Stroke volume</p>
<p>End systolic volume</p>
Where on the graph does Isovolumeric ventricular contraction and relaxation occur?
<p>What is happening at stages A, B, C and D?</p>
<p>A - mitral valve opens</p>
<p>B - Mitral valve relaxes - pressure starts rising because the ventricle starts to relax</p>
<p>C - Aortic valve opens opens becuase pressure in the ventricle is greater than that of the aorta (end diastolic volume)</p>
<p>D -aortic valve closes – End systolic volume</p>
<p>What is happening in the atrium during ejection phase?</p>
<p>Filling with blood from the lungs (pulmonary vein)</p>
<p>What are average values for EDV and ESV?</p>
<p>EDV = 140 ml</p>
<p>ESV = 60 ml</p>
<p>Stroke volume is therefore about 80 ml</p>
What is responsible for these two sounds?
What is the cause of this abnormal sound?
<p>What is responsible for the abnormal sound seen in the phonocardiogram?</p>
What is responsible for the abnormal sound on the phonocardiogram?
Septal defect
