| 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 |
Ch.18 LTI-MA 509
