Flashcards in Electrical Properties of the Heart and Conduction System Deck (41):
Sinoatrial Node. Normal site of origin of the electrical impulse. The hearts natural pacemaker. SA node travels through the right and left atria resulting in the atrial contraction.
Atriocentricular node. Transiently slows electrical impulse.
Bundle of His
A continuation of the AV node. Bundle branches procede the Bundle of His.
Fibers that go to the left and right ventricles.
The ability of cells to respond to electrical impulses.
The ability of cells to conduct electrical impulses.
The ability to generate an impulse to contract without the need of a nerve stimulus. (CARDIAC CELLS)
Hearts rate of contraction (monitored by various systems in the body)
Hearts rate of electrical conduction (monitored by various systems in the body)
Hearts strength of contraction (monitored by various systems in the body)
Detect chemical changes in the blood.
Sense the pressure in the heart or arteries.
Strength of heart muscle contraction.
Slows heart by affecting AV node
Alpha OR Beta effects; depending on what nerve receptor is stimulated.
Alpha receptors are stimulated resulting in vasoconstriction
Beta receptors are stimulated resulting in increased inotropic,dromotropic, and chronotropic states.
Hormone that has a greater stimulatory effect on BETA receptors.
Hormone that has a greater stimulatory effect on ALPHA receptors.
IONS. Charged chemicals.
Sodium. Concentration is greater OUTSIDE of the cell.
Potassium. Concentration is greater INSIDE of the cell.
Cellular Electrical Charged difference across the membrane. Measured in Millivolts.
Negative Electrical Pote - Extracellular space is more positively charged than the intracellular space.
Resting cells normally have a NET negative charge with respect to the outside of the cell.
Heart cell gets a stimulus from the conduction system. Sodium (Na+) rushes in, along with some calcium (Ca2+). Changing the charge of the cell. Makes the intracellular slightly positive charged.
The process in which the cell can get back to the POLERIZED state (net negative).Depolerization slows down...Potassium (k+) starts to flow out of the cell, and the sodium potassium pump starts to activate based on the charge needs of the cell to keep it at a polarized state (net negative).
Absolute Refractory Period
EARLY phase of repolarization when the cell contains a large concentration of ions that it cannot be stimulated to depolerize.
Relative Refractory Period
LATE stage of repolarization, cells are able to respond to a stronger stimulus.
Electrocardio gram a graphic recording of the electrical activity of the heart
Occurs first. Represents the electrical impulse through the atria
Flat line between the p and r... Represents the time delay within the AV node
QRS complex. Represents the DEPOLARIZATION of the ventricle contraction.
The pause after the QRS complex. This is where repolarization is beginning.
Represents completion of REPOLARIZATION.
From contraction of the myocardium to the next contraction
Ventricular contraction. Blood is pumped to the body (systemic) and lungs (pulmonary) via contraction of the ventricles.
Pressure in the AORTA.
Amount of blood ejected into the aorta from the left ventricle per contraction