E1: Basic Electrocardiography Flashcards
What are the two basic cell types in the heart?
Myocardial cells and conducting cells
What allows for rapid conduction of electrical impulses from one cell to the next?
Gap junctions in the intercalated discs
What are the 4 key properties of myocardial cells?
Automaticity, excitability, conductivity, and contractility
What are the two kinds of cells in the conductive pathway?
Pacemaker cells and electrical conducting cells
What is the hearts primary pacemaker?
SA node
What is the function of the AV node?
The AV node slows the signal to allow the atria to contract and empty as much blood as possible into the ventricles for stronger contraction and improved cardiac output
What does the polarized state of myocardial cells consist of?
Negatively charged ions inside the cells and positively charged ions outside the cell
What are bipolar leads? Which leads are bipolar leads?
- they have electrodes of opposite polarity
- Limb leads (leads I, II, and III)
How does movement toward a positive electrode appear on an EKG tracing?
Above the baseline
What does the P wave represent?
Atrial depolarization
What are the QRS wave represent?
Ventricular depolarization
What does the T wave represent?
Ventricular repolarization
