The result of increased preload on cardiac muscle is?: (A) Lengthening of muscle fibre, (B) Shortening of muscle fibre, (C) No effect, (D) Variable effect
Answer is A. ANSWER: (A) Lengthening of muscle fibreREF: Ganongs 22nd edp. 572Preload is determined by amount of blood reaching the heart; it causes an increase in the muscle fiber length and therefore according to frank starling's law increased force of contraction