Which of the following functions of the left ventricle is NOT a phase in the cardiac cycle?

The function of the left ventricle that is not considered a distinct phase in the cardiac cycle is pressure. The cardiac cycle is typically divided into specific phases: filling, contraction, and relaxation.

During the filling phase, also known as diastole, the left ventricle fills with blood from the left atrium as the heart muscle relaxes. In the contraction phase, which corresponds to systole, the left ventricle contracts to pump blood into the aorta. Finally, during the relaxation phase, the ventricle prepares to fill again as it undergoes a period of rest after contraction.

While pressure is a critical factor influencing the function of the heart, it represents a measurement or a condition rather than a phase of the cycle. The left ventricle's ability to generate pressure is a result of these distinct phases occurring, but it does not constitute a phase itself. Thus, the emphasis on filling, contraction, and relaxation clearly distinguishes them as the primary phases involved in the cardiac cycle rather than pressure.