MEDICAL
HEART AND PERICARDIUM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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40-60 bpm
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80-90 bpm
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60-80 bpm
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60-100 bpm
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Detailed explanation-1: -The SA node is considered the pacemaker of the heart. Its electrical signals normally cause the atria of an adult’s heart to contract at a rate of about 60 to 100 times a minute. Disturbance anywhere along this electrical pathway can cause irregular heartbeats (arrhythmia).
Detailed explanation-2: -The SA node fires at a normal rate of 60–100 beats per minute (bpm), and causes depolarization in atrial muscle tissue and subsequent atrial contraction.
Detailed explanation-3: -The SA node starts the sequence by causing the atrial muscles to contract. That’s why doctors sometimes call it the anatomical pacemaker. Next, the signal travels to the AV node, through the bundle of HIS, down the bundle branches, and through the Purkinje fibers, causing the ventricles to contract.