The Cardiovascular System

Intrinsic Conduction System
1. The intrinsic conduction system consists of __autorhythmic cardiac______ cells that initiate and distribute __impulses___ throughout the heart.
2. The intrinsic conduction system coordinates heart activity by determining the direction and speed of _heart depolarization___. This leads to a coordinated heart contraction.

3. List the functions for the following parts of the intrinsic conduction system:

a. SA Node __initiates the depolarizing impulse and sets the pace for the entire beat___
b. Internodal Pathway __link between the SA node and the AV node__
c. AV Node __delay occurs allowing atria to contract___
d. AV Bundle (Bundle of His) _link between atria and ventricles__
e. Bundle Branches __convey impulses down the interventricular septum___
f. Purkinje Fibers ___convey the depolarization throughout the ventricular walls_____

4. The action potentials spread from the autorhythmic cells of the intrinsic conduction system (electrical event) to the _contractile__ cells. The resulting mechanical events cause a heartbeat.
5. A tracing of the electrical activity of the heart is called a/an __electrocardiogram__.
6. What do the following waveforms reflect?

a. wave ___atrial depolarization___
b. QRS complex ___ventricular depolarization____
c. T wave __ventricular repolarization___

7. In a normal ECG wave tracing, atrial repolarization is hidden by __QRS Complez__.
8. Note: Electrical events lead to mechanical events. For example, the P wave represents __atrial_ depolarization, which leads to atrial _contraction___.
9. A left bundle branch block would have a wider than normal wave for the __QRS complex_. (Quiz section) 10. An abnormally fast heart rate (over 100 beats per minute) is called: __tachycardia___. (Quiz section)