Cardiac Physiology Class 1

Cardiac Cycle Class 2

Figure 20-17 Pressure and Volume Relationships in the Cardiac Cycle. Step 1 ONE CARDIAC CYCLE QRS complex QRS complex Electro- cardiogram (ECG) P T P ATRIAL DIASTOLE ATRIAL SYSTOLE ATRIAL DIASTOLE ATRIAL SYSTOLE VENTRICULAR DIASTOLE VENTRICULAR SYSTOLE VENTRICULAR DIASTOLE 120 5 6 Aorta 90 1 2 Pressure (mm Hg) 60 3 Left ventricle 4 4 7 5 6 7 30 Left atrium 8 2 1 3 8 130 End-diastolic volume 3 2 Left ventricular volume (mL) 1 Stroke volume End-systolic volume 6 50 100 200 300 400 500 600 700 800 Time (msec)

Cardiodynamics Class 3

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

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) = b Factors affecting cardiac output