Ie changing aortic bp during ejection of blood from

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Unformatted text preview: pressure, the mitral and tricuspid valves will open and ventricles fill Mitral and tricuspid valves open the atria to the ventricles ? Ventricular Relaxation (cont) •  Diastasis-inflow to ventricles is reduced. •  Atrial systole-atrial contraction actively pumps about 25-30% of the inflow volume and marks the last phase of ventricular relaxation (diastole) Ventricular Volumes •  End Diastolic Volume-(EDV) –  volume in ventricles at the end of filling •  End Systolic Volume- (ESV) –  volume in ventricles at the end of ejection •  Stroke volume (EDV-ESV) –  volume ejected by ventricles •  Ejection fraction –  % of EDV ejected (SV/EDV X 100%) –  normal 50-60% Most of Diastole- AP>LAP>LVP Most of systole- LVP>AP>LAP Ex. EDV= 160 ESV= 80 SV 160- 80 = 80 80/160= 50% SV/EDV= ejection fraction. 109 Terms Preload is when the ventrical fills Atrial Pressure Waves •  A wave •  C wave –  associated with ventricular contraction •  bulging of AV valves and tugging on atrial muscle Bulging of the AV valve as a result of the Afterload is arterial pressure against whichthe ventrical must contract Cardiac outout is proportionate to the body's metabolic demand Left ventrical needs to pump more and do more work in order to maintain equalibrium When it begins to fail there is heart failure •  Preload-stretch on the wall prior to contraction (proportional to the EDV) •  Afterload-the changing resistance (impedance) that the heart has to pump against as blood is ejected. i.e. Changing aortic BP during ejection of blood from the left ventricle Left atrial pressure gets higher then right atrial pressure –  associated with atrial contraction •  V wave backflow of blood from ventrical to atria –  associated with atrial filling 9 AV valves prevent backflow of blood from the ventricals to the atria during systole Semilunar valves prevent backflow if blood from the aorta and pulmonary arteries into the ventricals during diastole 107 Papillary muscles do not help in the closing of valves Instead the aid in preventing the valve from bulging back into the atria too far 107 Function of Valves •  Open with a forward pressure gradient –  e.g. when LV pressure > the aortic pressure the aortic valve is open Heart Valves •  AV valves –  Mitral & Tricupid •  Thin & filmy •  Chorda tendineae act as check lines to prevent prolapse •  papillary muscles-increase tension on chorda t. •  Close with a backward pressure gradient –  e.g. when aortic pressure > LV pressure the aortic valve is closed •  Semilunar valves Semilunar valves are found in the ventricles –  Aortic & Pulmonic Aortic is in LV •  stronger construction Pulmonic is in the RV Semilunar valves have no chordae tendineae Valvular dysfunction •  Valve not opening fully –  stenotic Heart Murmur Considerations •  Timing –  Systolic •  aortic & pulmonary stenosis •  mitral & tricuspid insufficiency Blowing sound indicates a systolic memur •  Valve not closing fully –  insufficient/regurgitant/leaky •  Creates vibrational noise –  aka murmurs Can be both stenotic and insufficient if the valve is stuck partially open –  Diastolic •  ao...
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This note was uploaded on 05/03/2011 for the course PHYS 339 taught by Professor Free during the Spring '11 term at Palmer Chiropractic.

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