PATHOLOGY

Detailed explanation-1: -The P wave represents the electrical depolarization of the atria. In a healthy person, this originates at the sinoatrial node (SA node) and disperses into both left and right atria.

Detailed explanation-2: -In sinus rhythm, the observed Ta wave in the PR segment represents the early part of atrial repolarization.

Detailed explanation-3: -In the given diagram the P-wave represents the electrical excitation (or depolarization) of the atria, which leads to the contraction of both the atria. The QRS complex represents the depolarization of the ventricles, which initiates the ventricular contraction.

Detailed explanation-4: -On the ECG, all waveforms can be categorized into two groups: depolarization and repolarization. Ventricular depolarization is depicted by the QRS complex, and ventricular repolarization is represented by the J (Osborn), T, and U waves.