How do the heart valves function to provide unidirectional blood flow? What factors determine the level of the systolic and diastolic blood pressure? What are the major causes of heart disease? What...

How do the heart valves function to provide unidirectional blood flow? What factors determine the level of the systolic and diastolic blood pressure?

What are the major causes of heart disease? What is the difference between rheumatic fever and rheumatic heart disease?