study guide 1 Flashcards
PRELOAD
The blood volume that is going into the heart through the coronary artery
INOTROPIC
Modifying the force or speed of contraction of muscles.
CHRONOTROPIC
Affecting the rate or timing of a physiologic process, as the heart rate.
AUTOMATICITY
The ability of pacing cells to spontaneously initiated an action potential
EXCITABILITY
The ability of heart to respond in response to an electrical stimulus and generate an action potential
CONDUCTIVITY
The ability to conduct impulses down through the heart muscle
DEPOLARIZATION
When the heart cell receives an electrical impulse.
REPOLARIZATION
Is what happens when the heart cell is recharging itself.
CARDIAC OUTPUT
The amount of blood the heart pumps through the circulatory system in a minute.
AFTERLOAD
The blood volume that is pumped out into the body.
DROMOTROPIC
Is one which affects the conduction speed in the AV node, and subsequently the rate of electrical impulses in the heart.
P – WAVE / PR INTERVAL
The period, measured in milliseconds, that extends from the beginning of the P wave (the onset of atrial depolarization) until the beginning of the QRS complex (the onset of ventricular depolarization); it is normally between 120 and 200ms in duration.
QRS COMPLEX
A name for the combination of three of the graphical deflections seen on a typical electrocardiogram (EKG or ECG). It is usually the central and most visually obvious part of the tracing. It corresponds to the depolarization of the right and left ventricles of the human heart.
T – WAVE
Represents the repolarization (or recovery) of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period.
CONTRACTILITY
A measure of cardiac pump performance, the degree to which muscle fibers can shorten when activated by a stimulus independent of preload and afterload.
