Telemetry Exam Study Guide

electrical properties of the heart - Answer-1-automaticity 2-excitability 3-conductivity 4-contractility automaticity - Answer-=the ability of cardiac cells to depolarize spontaneously w/o external stimuli -cells able to modify membrane to pull in Na+ while K+ exits -rapid depolarization when threshold potential is reached -only certain cells have property of automaticity: SA node, AV node, bundle of HIS, purkinje network influence of the nervous system - Answer-SYMPATHETIC: affects atria and ventricles. increases HR and conduction PARASYMPATHETIC: affects only the atria. decreases HR, conduction and irritability excitability - Answer-=capability of cardiac cells to depolarize in response to a stimulus -all cardiac cells have this property conductivity - Answer-=property of some cardiac cells that enables them to transmit electrical impulses -electrical cells of the heart are arranged in a system of pathways=CONDUCTION SYSTEM contractility - Answer-=ability of atrial and ventricular muscle cells to shorten their fiber length in response to an electrical stimulation, generating sufficient pressure to propel blood foward rates of conduction system - Answer-SA node= 60-100 bpm AV node= 40-60 ventricles= 20-40 electrocardiogram (EKG or ECG) - Answer--graphic record -changes in magnitude, direction of electrical activity -generated by depolarization and repolarization of the atria and ventricles -detected by electrodes components of the EKG - Answer-p wave QRS t wave u wave PR interval QT interval