Flashcards in Phase 3 Cardiology Deck (12)
The heart is primarily composed to two different types of cardiac cells. What are they? What do they do?
1. Conductive cells - initiate electrical activity and conduct it through the heart.
2. Contracting cells - respond to the electrical stimulus and contact to pump the blood.
The electrical cells in the heart have a unique property called "automaticity." What is automaticity?
Automaticity means that the cardiac cells can discharge an electrical current without an external stimulus.
The electrical stimulus generated in the heart occurs in three distinct phases. What are those phases?
Which phase of the cardiac electrical stimulus is know as the "ready phase?" During this phase, positive charges on the outside of the cell is balanced by negative charge on the inside of the cell.
***With electrical charges balanced, there will be no movement of electricity***
Which phase of the cardiac electrical stimulus is know as the "discharge phase?" During this phase, two chemicals trade places, causing an electrical shift and subsequent charge.
***Electrical shift causes a wave like motion through the heart***
Which phase of the cardiac electrical stimulus is know as the "recovery phase?" During this phase, the electrical state of the heart returns to its normal state.
What subcategory of autonomic nervous system affects both the atria and the ventricles?
Sympathetic Nervous System
***increases heart rate, conduction and irritability of the heart***
What subcategory of autonomic nervous system affects only the atria?
Parasympathetic Nervous System
***decreases heart rate, conduction and irritability of the heart***
What does the P-wave on an EKG denote?
What does the QRS-wave on an EKG denote?
Ventricular depolarization (atrial repolarization)
What does the T-wave on an EKG denote?