It depdends: There are many causes of toe spasms/cramps and it is important to identify the source. Cramps and spasms can be due to dehydration and low potassium. But they can also be due to a nerve conditions as well. I recommend you see a specialist for further evaluation. ...Read more.
1 The SA node (called the pacemaker of the heart) sends out an electrical impulse. 2  The upper heart chambers (atria) contract. 3  The AV node sends an impulse into the ventricles.  The lower heart chambers (ventricles) contract or pump.
Pacemaker cells in the SA node A) are special neurons that convey signals from the brain to the heart. B) can spontaneously depolarize. C) also contract with the rest of the cells in the heart wall. D) have a well-defined resting potential. E) All of the answers are correct.