Ex 3: Electrical Properties of the Heart Flashcards
What are the two “circuits” or “pumps” for circulation?
pulmonary circuit and systemic circuit
What circuit has low pressure?
pulmonary circuit
What circuit has high pressure?
systemic circuit
What are the two types of cardiac muscle fibers?
contractile and conducting
Where are the contractile fibers located in the heart?
atria and ventricles
Where are the conducting fibers located?
deeper below the endocardium
Where are the conducting fibers located?
deeper below the endocardium
What is known as the “pacemaker”?
Sinoatrial node
What are the four special tissues that set the impulse and the pace?
Sinoatrial node, atrioventricular node, AV bundle/Bundle of His, Purkinje fibers
What is known as the ectopic pacemaker?
when a region of the heart other than the SA node assumes the role of cardiac pacemaker (example would be AV node and His-purkinje system)
The cardiac action potential can be conducted from cell to cell due to what?
gap junctions
What is pacemaker potential?
the resting membrane potential initially starting at -60mV then drifts upward due to sodium inflow without compensating potassium outflow
What is the cardiomyocytes stable RMP?
-90 mV
What is the intrinsic heart rate?
60-100 beats per minute
What is bradycardia?
low heart rate
