Summary

The cardiovascular_system delivers oxygen and nutrients and removes waste. It includes heart_chambers (atria, ventricles) and blood_vessels (arteries, veins, capillaries). The cardiac_cycle has systole and diastole; normal heart sounds are S1_S2. electrical_conduction starts at the SA node, then AV node, bundle branches, Purkinje fibers. Key measures: heart_rate, blood_pressure, and cardiac_output = stroke volume x heart rate. Adequate perfusion supports tissue oxygenation; reduced flow can cause ischemia.