ch 8 The Cardiac Conduction System and EKG Tracings

What three things are needed for the heart to pump enough blood to meet the needs of the body?

1. Electrical system of the heart working properly

2. Mechanical components (muscle and valves) healthy

3. Enough blood to pump through an intact vascular system

Sinoatrial node

part of the electrical conduction system of the heart, located in the upper part of the right atrium and acting as the primary pacemaker of the heart, with an intrinsic rate of 60–100 BPM; also called the SA node or sinus node.

Atrioventricular (AV) node/ gateway

1. Slows down to allow the atria to empty.

2. It is the reason why the atria and ventricles don’t contact together

part of the electrical conduction system of the heart, located at the bottom of the right atrium, behind the tricuspid valve, with an intrinsic rate of 40–60 BPM.

Atrioventricular (AV) junction located

between the AV node and the bundle of His

Bundle of His

part of the electrical conduction system of the heart, located in the upper part of the interventricular septum, with an intrinsic rate of 40–60 BPM; also called AV bundle.

Bundle branches

part of the electrical conduction system of the heart; they divide from the bundle of His and carry the electrical impulse to the walls of the ventricles. an intrinsic rate of 40–60 BPM

Purkinje Fibers

part of the electrical conduction system of the heart; they divide from the bundle branches and have an intrinsic rate of 20–40 BPM.

We need a pacemaker

Irritable

in reference to the cardiac conduction system, more likely to initiate an electrical impulse at the wrong time or in the wrong location it is a problem.

the primary Pace maker

SA node

P wave = atrial depolarization = __________ of the atria

QRS complex = ventricular depolarization = __________ of the ventricles

T wave = ventricular repolarization = __________ of the ventricles

contraction, contraction, relaxation