IMMUNOLOGY

Detailed explanation-1: -Normally, the heartbeat starts in the right atrium in a group of special heart cells called the sinoatrial (or sinus) node. These cells act as a pacemaker for the heart. The heart’s pacemaker sends out an electrical signal (impulse) that spreads throughout the heart along electrical pathways.

Detailed explanation-2: -An electrical stimulus is generated by the sinus node (also called the sinoatrial node, or SA node). This is a small mass of specialized tissue located in the right upper chamber (atria) of the heart. The sinus node generates an electrical stimulus regularly, 60 to 100 times per minute under normal conditions.

Detailed explanation-3: -Cardiac muscle cells are the contracting cells that allow the heart to pump.

Detailed explanation-4: -To do this, it relies on a specialized network of cells called the cardiac conduction system. It’s also known as your heart’s electrical system. Cells in the cardiac conduction system can generate electrical impulses and then distribute the signal throughout your heart.