Topic 3 Circulatory System: Circulatory System Equations

Question 1

• Stroke volume: volume of blood discharged from the ventricles with each contraction
• Cardiac output: volume discharged from ventricle each minute

Answer 1

1. Cardiac output (CO) = stroke volume (SV) x heart rate (HR)

Question 2

• EDV: volume of blood in the ventricle just before contraction
• ESV: blood in ventricle at end of contraction/systole

Answer 2

2. Stroke volume = end diastolic volume (EDV) – end systolic volume (ESV)

Question 3

• SVR: resistance controlled by vasoconstriction/dilation – the larger the diameter, the less resistance

Answer 3

3. Blood pressure (BP) / Mean atrial pressure (MAP) = CO x Systemic Vascular Resistance (SVR)