the heart's natural pacemaker is located at sinoatrial ( sa ) node.
the heart's natural pacemaker is located at sinoatrial ( sa ) node.
where is the heart's natural pacemaker located?
sinoatrial ( sa ) node
the contraction of cardiac muscle (heart muscle) in all animals is initiated by electrical impulses known as action potentials. the rate at which these impulses fire controls the rate of cardiac contraction, that is, the heart rate. the cells that create these rhythmic impulses, setting the pace for blood pumping, are called pacemaker cells, and they directly control the heart rate. they make up the cardiac pacemaker, that is, the natural pacemaker of the heart. in most humans, the concentration of pacemaker cells in the sinoatrial (sa) node is the natural pacemaker, and the resultant rhythm is a sinus rhythm.
cardiac pacemaker
an ectopic pacemaker can reside within a part of the electrical conduction system of the heart, or within the muscle cells of the atria or ventricles. when an ectopic pacemaker initiates a beat, premature contraction occurs. a premature contraction will not follow the normal signal transduction pathway, and can render the heart refractory or incapable of transmitting the normal signal from the sa node. location of the pacemaker can also change its effect on the sa node and its rhythm. an ectopic pacemaker located in the atria is known as an atrial pacemaker and can cause the atrial contraction to be faster. an ectopic pacemaker situated near the av node and the septum is known as a junctional pacemaker. the pacemaker that is operating in the ventricles is known as the ventricular. other such ectopic pacemakers can even lie within the pulmonary vein and thoracic vein walls.
ectopic pacemaker