PHSI 208 Lecture Notes - Lecture 29: Pulmonary Circulation, Pulmonary Hypertension, Stroke Volume
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End diastolic volume (edv) = the maximal volume in the ventricle, after ventricular filling (ventricular diastole) 70 kg man at rest ~135 ml. End-systolic volume (esv) = the minimal amount of blood in the ventricles. The blood left after ventricular contraction, ~65 ml. Stroke volume (sv) = amount of blood ejected during a single ventricular contraction, ~70 ml. The esv provides a safety margin, a more forceful contraction of the heart will cause a larger stroke volume resulting in a decrease in the esv. You need additional blood in the ventricles to compensate for changes in contractility. Stroke volume can increase to as high as 100 ml and is modulated by the autonomic ns (especially by sympathetic division), venous return and by certain drugs. Total blood flow (cardiac output) = heart rate x stroke volume. Flow of blood delivered from one ventricle in a given time period (usually 1 min) is the cardiac output (co)