Chambers - pockets in the heart that collect and squeeze blood
Peri- outer layer ; Pericarditis for inflammation of the heart sac (pericardium)
Cardio- heart, circulatory
Pacemaker - stimulates heart and contractions
Positive and Negative Think of a battery standing up. Negative is the bottom. Positive is top; Action potential are the impulses found in muscle cells. This includes your heart muscle and skeletal muscles 
Sodium ; Sodium entering the cell via channels controls voltage. Drugs that interact with sodium channels are used to treat heart conditions and seizures that involve impulses. Cardiac action potential, irregular heart beats, seizures
Potassium ; Sodium potassium pump is used to pump ions into and out of the cell
Calcium ; Calcium enters the cell to slow impulses in the heart. This helps keep the heart in a normal rhythm so each chambers knows when to pump
Collagen - connective tissue It is like the coating on your chager cables. Keeps the electricity from crossing boundaries; Collagen does not conduct electricity.
Coronary - blood vessels of the heart ; The heart pumps blood to the body, but also requires blood for itself. If these vessels get blocked then the heart tissue dies. A heart attack occurs
Tachycardia - abnormal fast heart rate Tachy- is fast; Abnormal heart rates can be fast or slow
