-atria relax. ventricles contract. blood in ventricles compressed > AV forced shut.
-pressure still not sufficient to open semilunar valvees. vent contracting = no blood leaving, isometric contraction phase.
Events in Left Side of Heart IV
-atria in diastole. ventricles systole. - vent pressure increases suffiently to exceed aortic pressure and semilunar valves open -> blood enters aorta (swells + atrial pressure increases) = ventricular ejecction phase
Events in Left Side of Heart V
ventricles relax. pressure decreases in ventricle. blood flow backwards from aorta + pulmonary arteries. closes semilunar valves. brief increase in aortic pressure (dictrotic notch)
Events in Left Side of Heart VI
ventricles relax. longer for pressure to fall in ventricles. AV valves closed. ISOMETRIC RELAXATION PHASE.
Atria + vent = diastole.
vent systole-> atria slowly filling w/blood
vent/atria P increase slightly
Events in Left Side of Heart VII
Ventricular pressure falls below level. all valves open and ventricle begins filling again. atria pressure decreases slightly and vent pressure increases when chambers fill with blood
Heart Sounds - LUB
LUB= reverse blood flow due to closure of the AV valves, at the beginning of vent contraction, or systole. When the pressure in the vent rises above the pressure in the atria, venous blood flow entering the vent is pushed back toward the atria
Heart Sounds - DUB
Results from closure of aortic and pulmonary semilunar valves at beginning of ventricular diastole, lasts longer
Ch.18 LTI-MA 509
