Which determinant of stroke volume corresponds to the heart muscle's responsiveness to filling?

Prepare for the Anatomy and Physiology II Milestone 1 Test with engaging questions, in-depth explanations, and focused study resources. Start your journey to excel in your exam!

Multiple Choice

Which determinant of stroke volume corresponds to the heart muscle's responsiveness to filling?

Responsiveness of the heart muscle to filling is determined by preload—the stretch on the ventricular fibers at the end of diastole caused by venous return. When the ventricle fills more, the fibers are stretched more and, via the Frank-Starling mechanism, generate a stronger contraction, increasing stroke volume up to the heart’s physiological limit. Afterload is the pressure the ventricle must overcome to eject blood, not how it responds to filling. Contractility is the intrinsic strength of the myocardium independent of filling, and heart rate mainly affects filling time and overall cardiac output rather than the heart’s responsiveness to the amount of filling.

Responsiveness of the heart muscle to filling is determined by preload—the stretch on the ventricular fibers at the end of diastole caused by venous return. When the ventricle fills more, the fibers are stretched more and, via the Frank-Starling mechanism, generate a stronger contraction, increasing stroke volume up to the heart’s physiological limit. Afterload is the pressure the ventricle must overcome to eject blood, not how it responds to filling. Contractility is the intrinsic strength of the myocardium independent of filling, and heart rate mainly affects filling time and overall cardiac output rather than the heart’s responsiveness to the amount of filling.

More practice questions