This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'All of the following factors normally increase the length of the ventricular cardiac muscle fibers except: \nSelect and explain. \nA. Increased venous tone., B. Increased total blood volume, C. Increased negative intrathoracic pressure., D. Lying-to-standing change in posture', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. Lying to standing change in posture When a person moves from a supine position to standing position volume of blood pools in the lower extremity because of high compliance of veins & venous return decreases. As a result of decreased venous return the length of ventricular cardiac muscle fibres is decreasedQ and so the cardiac output in accordance with frank-sterling law.', 'role': 'assistant'}]