The Cardiac Cycle Flashcards
Transition from rest to exercise:
Diastole is shortened during exercise
Diastole
Relaxation Period> Filling; ⅔ of the time at rest
Systole
Contraction Phase> Ejection; ⅓ of the time at rest
Phase 1
Ventricular Filling, AV valves open; Occurs during mid to late diastole; Atrial contraction pushes additional blood through
Phase 2
Systole has two periods
Isovolumetric Contraction, AV Valves and Semilunar Valves Closed; Ventricular Ejection: Semilunar Valves Open
Phases 3
Isovolumetric Relaxation
Both AV Valves and Semilunar Valves Closed
What causes a heart attack?
Coronary Artery is blocked and myocardial walls are damaged; Causes inadequate oxygen and nutrients delivery and built up acidity by proton generation in myocardial wall; Cannot create electrical impulses for coordinated contraction
What protects against heart attack?
Exercise training; Increases number of antioxidant enzymes that are available in the heart tissue and heat shock proteins; regularly trains the heart to tolerate reperfusion