The Heart part 3

is a small upward deflection on the ECG it represents atrial depolarization which spreads from the SA nodes through contractile fibers in both atria

begins as downward deflection, continues as a large upright, triangular wave and ends as a downward wave.  It represents rapid ventricular depolarization, as the action  potential spreads through ventricular contractile fibers

a dome shaped upward deflection.  It indicates ventricular re polarization and occurs just as the ventricles are starting to relax.

refers to the phase of contraction.  the atria and ventricles depolarize and then contract at different times.

the phase of relaxation

includes all the events associated with on heartbeat.  Thus it consists of a systole and diastole of the atria plus systole and diastole of the ventricles

the atria are contracting the same time the ventricles are relaxing

the ventricles are contracting the same time the atria are relaxing

during this interval cardiac muscle fibers are contracting exerting force but are not yet shortened.  Both semilunar valves and AV valves are closed

the period when the SL valves are open

the volume remaining in each ventricle at the end of systole

the volume ejected per beat from each ventricle, equals end-diastolic volume minus end systolic volume

the atria and ventricles are both relaxed.

caused by ventricular repolarization as the ventricles relax pressure within the chambers falls

after the sl valves close there is a brief interval when ventricular blood volume does not change because all four valves are closed.

as the ventricles continue to relax.  The pressure falls quickly. When ventricular pressure falls below atrial pressure, the av valves open and this begins

during each cardiac cycle there are four of these. but in a normal heart only the first and second heart sounds are loud enough to hear

the first sound.  Is louder and a bit longer than the second sound.  it is caused by blood turbulence associated with closure of the AV valves soon after ventricular systole begins

the second heart sound which is shorter and not as loud as the first.  it is caused by blood turbulence associated with closure of the SL valves at the beginning of the ventricular diastole

is an abnormal sound consisting of a clicking rushing or gurgling sound that either is hear before, between or after the normal heart sounds or may mask the normal heart sounds.