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.
How does the heart conduction system work?
A network of specialized muscle cells is found in the heart’s walls. These muscle cells send signals to the rest of the heart muscle causing a contraction. This group of muscle cells is called the cardiac conduction system.
How long does it take for an impulse to reach the base of LV?
These factors mean that it takes the impulse approximately 100 ms to pass through the node. This pause is critical to heart function, as it allows the atrial cardiomyocytes to complete their contraction that pumps blood into the ventricles before the impulse is transmitted to the cells of the ventricle itself.
Does the brain controls the heart?
The brain stem sits beneath your cerebrum in front of your cerebellum. It connects the brain to the spinal cord and controls automatic functions such as breathing, digestion, heart rate and blood pressure.
How the heart contracts step by step?
The heartbeat happens as follows:
- The SA node (called the pacemaker of the heart) sends out an electrical impulse.
- The upper heart chambers (atria) contract.
- The AV node sends an impulse into the ventricles.
- The lower heart chambers (ventricles) contract or pump.