Question | Answer |
2 specialized types of cardiac muscle cells | contractile myocardial cells and non contractile autorhythmic cells |
__cells responsible for the mechanical pumping of the heart | contractile myocardial cells |
99% for cardiac muscle tissue are ___ cells | contractile myocardial cells |
___ cells of the conduction system are responsible for electrical stimulation of myocardial cells | non contractile autorhythmic cells |
__cells are 1% of cardiac muscle tissue | non contractile autorhythmic cells |
__cells spontaneously depolarize via slow movement of + ions through channels leading to threshold then generating an AP | autorhythmic cells |
AP travels throught the conduction system triggering the contraction of | the surrounding myocardial tissue |
different parts of the hearts conduction system have their own _ rate | autorhythmicity rate |
4 Components of the conduction system | SA node, AV node, AV Bundle, and Purkinje fibers |
autorhythmicity rate of 70 beats/min | SA node |
autorhythmicity rate of 50 beats/min | AV node |
autorhythmicity rate of 35 beats/min | AV bundle |
autorhythmicity rate of 30 beats/mini | Purkinje fibers |
a recording of the electrical changes that accompany the cardiac cycle | electrocardiogram (ECG) |
represents the depolarization of the atria as a wave of negativity spreads from the SA node toward the ventricles | P wave |
represents the spread of excitation throught the ventricular myocardium resulting in depolarization of ventricular muscle | QRS complex |
atrial repolarization is masked by | the large QRS deflection |
represents the repolarization of the ventricles | T wave |
represents the interval between the activation of the SA node and the AV node | P-R interval |
represents the interval between atrial depolarization and ventricular depolarization | P-R segment |
represents the interval between the end of the S wabe and the start of the T wave, ventricles are uniformly excited | S-T segment |
represents the interval of time between successive cycles | R-R interval |
flattened T wave= | heart muscle is ischemic |
enlarged ST segment= | acute myocardial infarctions |
enlarged R= | enlarged ventricles |