What does stroke volume represent in cardiac function?

Stroke volume refers specifically to the amount of blood that the heart's left ventricle ejects with each contraction. This measurement is crucial because it provides insight into the heart's efficiency and ability to supply sufficient blood to the body. A healthy stroke volume is essential for maintaining adequate circulation and supporting the metabolic needs of tissues.

When considering cardiac function, it's important to differentiate stroke volume from other concepts such as cardiac output, which is the total amount of blood pumped by the heart per minute. Stroke volume is just one component of this broader measurement. The concept of total blood volume in the circulatory system and the heart rate are also important but serve different roles in understanding heart function.

Therefore, option B is the most accurate representation of stroke volume in the context of cardiac physiology.