Physiology – MCQ 64 – Length of the ventricular cardiac muscle fibers
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
Correct answer : D. Lying to standing change in posture
When the person stands, 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).