Final answer:
The statement about the Frank-Starling law of the heart being an intrinsic regulator of stroke volume is true, as it describes how increased ventricular muscle stretch leads to stronger contractions and thereby increases stroke volume.
Step-by-step explanation:
The statement that the Frank-Starling law of the heart describes an intrinsic regulation of stroke volume is true. The Frank-Starling mechanism establishes the relationship between the ventricular stretch and contraction. It posits that, within physiological limits, the force of heart contraction is directly proportional to the initial length of the muscle fiber. Hence, the more the ventricular muscle stretches (within these physiological limits), the stronger the contraction becomes, leading to an increase in stroke volume. This process is affected by preload, which when increased, enhances the contractility of the cardiac muscle.