Final answer:
The ejection fraction, given that the left ventricle contains 80 mL of blood before contraction and ejects 60 mL during the contraction, is calculated as (60 mL / 80 mL) × 100%, resulting in 75%. This measure indicates the heart's pumping efficiency and is within the normal to high range.
Step-by-step explanation:
If the left ventricle contains 80 mL of blood before a contraction and ejects 60 mL during the contraction, the ejection fraction is calculated by dividing the stroke volume (SV), which is the amount of blood ejected during the contraction, by the end diastolic volume (EDV), which is the total amount of blood in the ventricle before the contraction. To find the ejection fraction, we use the formula: Ejection Fraction (EF) = (SV/EDV) × 100%. Using the given values, the EF = (60 mL / 80 mL) × 100%, which simplifies to 75%.
The ejection fraction is an important measure of the heart's pumping efficiency and is often used in the diagnosis and management of various heart conditions. The normal range for ejection fraction is approximately 55-70%, indicating that an ejection fraction of 75% is within the normal to high efficiency range for the heart's pumping ability. This correlates with the expected range of volume that remains in the ventricle after contraction, known as the end systolic volume (ESV).
The concept of ventricular systole, which encompasses two phases including the ejection phase, is critical in understanding the ejection fraction. During this phase, ventricles contract and eject blood from the heart, which is the mechanical process behind the calculation of ejection fraction.