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
Preload leads to - 
Select and explain. 
A. Isovolumetric relaxation, B. Isovolumetric contraction, C. Peripheral resistance, D. Parasympathetic nervous system activation
B: Isovolumetric contraction
Answer: B: Isovolumetric contraction 
Explanation: The amount of pressure on the muscles before the contraction starts is the preload. In regards to heart, preload is the amount of pressure on the ventricles at the end of diastole. At the end of diastole, isovolumetric contraction begins.