Comparison: As Nina envisioned, the heart has dual components:
* a mechanical component (rhythmic contractions and relaxations): the cardiac cycle, which consists of contraction phases (systole) that eject blood from the left ventricle and relaxation phases (diastole) that allow the cardiac cavity to fill,
* an electrical component (resulting from electric discharges), which directly governs the mechanical phase with which it is in perfect harmony.
The proper order is
*Electrical signals travel toward the heart.
*Signals received by the nodes in the atrium
*The atria contract
*Signals registered by the atrioventricular node
*Signals sent to the ventricles
*The ventricles contract
Explanation
* The electric impulse originates at a precise location within the heart (approximately a few millimeters in diameter) known as the sinus node, situated in the upper part of the right atrium.
This area comprises cells adept at generating an electric current. From the sinus node, the impulse spreads through the cardiac muscle (encompassing the two atria), prompting their contraction. It then converges at the heart's septum, at an electrical relay called the atrioventricular node (NAV).
From the atrioventricular node (NAV), the signal advances simultaneously to both the right and left ventricles through extremely rapid conductive pathways (the Hys bundle and the Purkinje network), causing the ventricles to contract.
