CARDIAC CYCLE - CONCEPT OVERVIEW PHYSIOLOGY INTERACTIVE INTRODUCTION PHYSIOLOGY INTERACTIVE In a single cardiac cycle, the ventricles fill to 130 mL , eject 70 mL , and contain 60 mL left over before filling again. Which of the following is the stroke volume (SV)? A. 190 mL B. 130 mL C. 70 mL D. 60 mL Second-degree AV block is a condition where the AV node fails to conduct some of the signals to the ventricles. For each cardiac cycle where the signal is blocked, describe expected changes to the ECG and behavior of the heart? Select two answers.

The stroke volume (SV) is the amount of blood ejected from the ventricles with each heartbeat. In your scenario, the ventricles fill to 130 mL and eject 70 mL, so the stroke volume is: **C. 70 mL**. This is the volume of blood that is efficiently pumped out of the heart, providing vital oxygen and nutrients to the body. In the case of a second-degree AV block, you might see specific changes on the ECG. There could be missing QRS complexes because not all signals from the atria are conducted to the ventricles, leading to a dropped beat. Additionally, the heart may exhibit a pattern of irregularity as some atrial impulses are conducted while others are not, reflecting the inconsistent behavior of the heart in response to the blocked signals.