ECG Flashcards
What are the types of cells located in the heart?
Specialized (pacemaker cells) and working myocardial cells
How is heart rate controlled normally?
Via the SA node
What do the specialized cells make up?
SA node, AV node, HIS bundle, bundle braches, and parking fibers
What is the absolute refractory period?
Myocardial cells cannot be stimulated to fire another action potential.
What does the absolute refractory period prevent?
Summated or tetanic contractions
What is relative refractory period?
Myocardial cells can still fire during this time, they just need a stronger than normal stimulation.
What causes the repolarization in fast and slow AP’s?
Due to increased potassium permeability.
What is cardiac output?
The volume of blood being pumped by the heart per unit time.
What is the equation for cardiac output?
Stroke volume X Heart rate
What does the baroreceptor reflex monitor?
Correct for arterial pressure by increasing or decreasing heart rate.
What does the bainbridge reflex monitor?
Responds to changes in blood volume.
What is normal sinus rhythm?
when the SA node is acting as the pacemaker.
What is tachycardia?
adult heart rate > 100beats/min.
What is bradycardia?
Adult heart rate
