AP BIOLOGY

Detailed explanation-1: -The sinus node is sometimes called the heart’s “natural pacemaker.” Each time the sinus node generates a new electrical impulse; that impulse spreads out through the heart’s upper chambers, called the right atrium and the left atrium (figure 2).

Detailed explanation-2: -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-3: -The heart’s electrical system SA node (sinoatrial node) – known as the heart’s natural pacemaker. The impulse starts in a small bundle of specialized cells located in the right atrium, called the SA node. The electrical activity spreads through the walls of the atria and causes them to contract.

Detailed explanation-4: -The SA node is the pacemaker of the heart and has an intrinsic rate of 60 – 100 bpm.

Detailed explanation-5: -An ectopic pacemaker also known as an ectopic focus or ectopic foci, is an excitable group of cells that causes a premature heart beat outside the normally functioning SA node of the heart.