PATHOLOGY MCQ
HEART
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Atria relaxes because the AV node fired a signal
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Atria contracts because the AV node fired a signal
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Atria contracts because the SA node fired a signal
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Atria relaxes because the SA node fired a signal
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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: -The P wave indicates atrial depolarization. The P wave occurs when the sinus node, also known as the sinoatrial node, creates an action potential that depolarizes the atria. The P wave should be upright in lead II if the action potential is originating from the SA node.
Detailed explanation-3: -The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. The SA node is considered the pacemaker of the heart.