Figure 18-2 Cardiac Cycle
Use Figure 18-2 to answer the following questions:
-What occurs at the area labeled "D" on the graph?
A) AV valve opens
B) semilunar valve opens
C) diastolic refilling begins
D) both AV valve opens and diastolic refilling begins
E) both semilunar valve opens and diastolic refilling begins

Question

Figure 18-2 Cardiac Cycle
Use Figure 18-2 to answer the following questions:
-What occurs at the area labeled "D" on the graph?
A) AV valve opens 
B) semilunar valve opens 
C) diastolic refilling begins 
D) both AV valve opens and diastolic refilling begins 
E) both semilunar valve opens and diastolic refilling begins

Quizplus · Accepted Answer

Area D represents the isovolumetric relaxation phase where the ventricles are relaxing and the pressure in the ventricles is decreasing. During this phase, the AV valves open, allowing blood to flow into the ventricles from the atria, and diastolic refilling begins as blood passively enters the ventricles. The semilunar valves are closed during this phase.