The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. ... 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.

What is the role of SA node?

The main role of a sinoatrial node cell is to initiate action potentials of the heart that can pass through cardiac muscle cells and cause contraction. ... This produces a positive change in membrane potential, known as depolarization, which is propagated throughout the heart and initiates muscle contraction.

Why is it called the SA node?

SA node: The SA node (SA stands for sinoatrial) is one of the major elements in the cardiac conduction system, the system that controls the heart rate. This stunningly designed system generates electrical impulses and conducts them throughout the muscle of the heart, stimulating the heart to contract and pump blood.