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mpworksheet62 - BIPN10 - Fortes Cardiac Cycle 1. Heart is...

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BIPN10 - Fortes Cardiac Cycle 1. Heart is relaxed, so blood flows from the veins (vena cavae) into the right atrium, and from the pulmonary veins into the left atrium. a. Diastole= when the pressure in the atria is ___greater_______(greater/smaller) than the pressure in the ventricles, the AV valves open and blood fills the ventricles. 2. At the end of diastole, the SA node depolarizes, depolarizing the atria and the atria contract. This tops off ventricles with blood. 3. As pressure in the ventricles begins to increase, and ventricles start to contract, the blood is pushed back into the atria. a. However, the __AV____ valves close, which causes the first heart sound. b. Ventricles become closed chamber because both the ____AV___ valves and ____semilunar/arterial___ valves are closed huge increase in pressure because can’t move a load= isovolumetric contraction. 4. The moment that pressure in the ventricles exceeds pressure in the arteries, the ____semilunar______ valves open and blood ejects into the arteries. 5. When ventricles begin to relax, the pressure in the ventricles begins to drop. a. Pressure drops the moment that ventricular pressure is ___less_______ (less/higher) than that in the arteries, the arterial valves ____close______ (open/close) Pressure-Volume graph: Label the above points (A-D) with what is happening at each point. Where would ESV and EDV be located on the graph? What is the pre-load and the after-load and where would it be located on the graph? . A Ventricle begins to fill (moment previous contraction is over). Volume of ventricle doesn’t start at zero because with every heartbeat, the ventricle doesn’t completely empty itself ESV (empties about half of ventricle) . B Ventricle has an increase in pressure because ventricular systole increases. Atria has just contracted to top off ventricle. EDV= (end diastolic) is important because it is the load the ventricle has to handle before it contracts. Known as the preload. . C Closing of AV valves causes huge increase in pressure isovolumetric contraction in which pressure shoots up but there is no change in volume. (close when pressure in ventricle> atria) .i After-load= pressure load that ventricle must overcome. Pressure must be greater in ventricles than the pressure in aorta (arteries). . D Moment ventricular pressure exceeds that in arteries, aortic valve opens and the blood ejects. Volume of ventricles decreases because of ejection. First heart sound= when pressure of the ventricle increases more than the atria to close AV valves at the beginning of systole. 2 nd heart sound= at the end of systole when the pressure in the ventricles is less than the arteries, the arterial valves closes.
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Diastole occurs between the _________ (1 st /2 nd ) and ___________ (1 st /2 nd ) heart sounds. Systole occurs between the _________ (1
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mpworksheet62 - BIPN10 - Fortes Cardiac Cycle 1. Heart is...

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