All of the following factors normally increase the length of the ventricular cardiac muscle fibers, except:: (A) Increased venous tone, (B) Increased total blood volume, (C) Increased negative intrathoracic pressure, (D) Lying-to-standing change in posture
Answer is D. When the person stands from a lying position, there is pooling of blood in the legs. This causes decrease in venous return and decrease in end diastolic volume (and length of ventricular cardiac muscle fibers).