This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal Muscle: Contraction and Excitation, Subject name: Physiology
Spontaneous contraction is seen in - 
Select and explain. 
A. Skletal muscles, B. Smooth muscles, C. Striated muscles, D. All of the above
B: Smooth muscles
Answer: B: Smooth muscles 
Explanation: Ans. is 'b' i.e., Smooth muscles o Single unit smooth muscles have their own-rhythmic contractility myogenic tone that is independent of the nerve supply.o The rate of contraction may be determined by the pacemaker regions present within the muscles.o The nervous influence only modulates their activity, i.e., the role of the nerves is to increase or decrease the rate of rhythmic contraction.