Cardiac Cycle

Diastole(ventricle relaxed) 1. isovolumetric relaxation -ventricles relaxed -BOTH VALVES CLOSED 2/3. ventricular filling -passive filling of ventricles form atria -AV OPEN -atria pressure > ventricle pressure -semi lunar closed ( arterial P > ventricle P) 4. atrial contraction -atria contract = tops off ventricle -VENTRICLE STILL RELAXED -SEMI LUNAR CLOSED: AV VALVE OPEN SYSTOLE BEGINS(ventricles contract) 5. isovolumetric contraction -ventricle 'contracts' but only generates tension and increased pressure -isometric movement =built up tension not contraction -BOTH VALVES ARE CLOSED -semi is closed since arterial P > ventricle P 6. ventricular ejection ventricles fully contract -blood pushed up into arteries to body parts -SEMI LUNAR OPEN : AV CLOSED -semi opens when ventricle P > arterial P

Lub = 1 = AV nodes close at "S' of QRS complex dub = 2 = semilunar close at T wave

-know these -end diastolic volume = 120mL -end systolic volume = 50mL -stroke volume = 120 - 50 = 70mL -cardiac output = SV*HR

-low = incomparison to ventricle when relaxed at 10mmHg -high at atrial systole(contraction) -high at ventricular contraction(back flow of pressure on AV node) -high during atrial filling(AV closed)

High- -atrial systole (increase in ventricular P) -ventricular contraction = increased tension = P -ejection = peak of P low- -low when AV valves open

Follows the peak of ventricular pressure (shape wise) peak = systolic pressure at 120mmHg when aortic P > ventricular P the SL valve closes -incisura occurs = backflow present against valve -pressure drops to 80mmHg(diastolic)

Diastolic filling from A-C -slight pressure decrease due to ventricular relaxation = more space than current volume B-C = atrial contraction C-D = ventricular contraction (increase pressure) -aortic valve opens at D D-E = ventricular ejection (increase pressure loss of volume) 50-120mL and 20-120mmHg pressure aortic P = 80-120mmHg

Increased volume (right)

Decreased volume (moves right) and increased pressure

Increased pressure and volume (left)