1. © 2015 Pearson Education, Inc. Figure 20-17 Pressure and Volume Relationships in the Cardiac Cycle. Aorta Electro- cardiogram (ECG) QRS complex P T ONE CARDIAC CYCLE QRS complex P ATRIAL DIASTOLE ATRIAL SYSTOLE VENTRICULAR DIASTOLE VENTRICULAR SYSTOLE ATRIAL DIASTOLE VENTRICULAR DIASTOLE ATRIAL SYSTOLE Left ventricle Left atrium 120 90 60 30 0 Pressure (mm Hg) End-diastolic volume End-systolic volume Stroke volume Time (msec) Left ventricular volume (mL) 130 50 0100200300400500600700800 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 6 Step 1

2. © 2015 Pearson Education, Inc. Figure 20-23 Factors Affecting Stroke Volume. Venous return (VR)Filling time (FT) Contractility (Cont) of muscle cells Afterload (AL) Preload Increased by sympathetic stimulation Decreased by parasympathetic stimulation Increased by E, NE, glucagon, thyroid hormones Increased by vasoconstriction Decreased by vasodilation End-diastolic volume (EDV) End-systolic volume (ESV) Factors Affecting Stroke Volume (SV) STROKE VOLUME (SV) Step 1

3. © 2015 Pearson Education, Inc. Figure 20-24b A Summary of the Factors Affecting Cardiac Output. Factors affecting heart rate (HR) Factors affecting stroke volume (SV) HEART RATE (HR) STROKE VOLUME (SV) = CARDIAC OUTPUT (CO) = Factors affecting cardiac output b