Search results
Results from the WOW.Com Content Network
Usage of the term "depolarization" in biology differs from its use in physics, where it refers to situations in which any form of polarity ( i.e. the presence of any electrical charge, whether positive or negative) changes to a value of zero. Depolarization is sometimes referred to as "hypopolarization" [1] [2] (as opposed to hyperpolarization).
Cortical spreading depression (CSD) or spreading depolarization (SD) is a wave of electrophysiological hyperactivity followed by a wave of inhibition. [3] Spreading depolarization describes a phenomenon characterized by the appearance of depolarization waves of the neurons and neuroglia [ 4 ] that propagates across the cortex at a velocity of 1 ...
During depolarization the impulse is carried from endocardium to epicardium, and during repolarization the impulse moves from epicardium to endocardium. In infective endocarditis , the endocardium (especially the endocardium lining the heart valves ) is affected by bacteria .
Numerous experimental studies have established that cortical spreading depolarization, the biological substrate for migraine aura, can discharge trigeminovascular afferents as a cause of head pain and by extension unilateral headache overlying the dysfunctional hemisphere in migraineurs with aura. [12]
Electrical waves track a systole (a contraction) of the heart. The end-point of the P wave depolarization is the start-point of the atrial stage of systole. The ventricular stage of systole begins at the R peak of the QRS wave complex; the T wave indicates the end of ventricular contraction, after which ventricular relaxation (ventricular diastole) begins.
The P wave is a summation wave generated by the depolarization front as it transits the atria. Normally the right atrium depolarizes slightly earlier than left atrium since the depolarization wave originates in the sinoatrial node , in the high right atrium and then travels to and through the left atrium.
Cardiovascular physiology is the study of the cardiovascular system, specifically addressing the physiology of the heart ("cardio") and blood vessels ("vascular").. These subjects are sometimes addressed separately, under the names cardiac physiology and circulatory physiology.
During frame 7, the depolarization is traveling through the largest amount of tissue in the atria, which creates the highest point in the P wave. Frames 11–12 depict the depolarization traveling through the AV node. Like the SA node, the AV node is too small for the depolarization of its tissue to be detected on most ECGs.