This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Smooth Muscle, Subject name: Physiology
Which of the following best describes an attribute of visceral smooth muscle not shared by skeletal muscle? 
Select and explain. 
A. Contraction is ATP dependent, B. Contracts in response to stretch, C. Does not contain actin filaments, D. High rate of cross-bridge cycling
B: Contracts in response to stretch
Answer: B: Contracts in response to stretch 
Explanation: An impoant characteristic of visceral smooth muscle is its ability to contract in response to stretch. Stretch results in depolarization and potentially the generation of action potentials. These action potentials, coupled with normal slow-wave potentials,stimulate rhythmical contractions. Smooth muscle contraction is dependent on both actin and ATP. However, the cross-bridge cycle in smooth muscle is considerably slower than in skeletal muscle, which allows for a higher maximal force of contraction.