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
Gate system for pain control at 
Select and explain. 
A. Substantia gelatinosa, B. Dorsal root ganglion, C. Both, D. None
A: Substantia gelatinosa
Answer: A: Substantia gelatinosa 
Explanation: The gate for pain control is the enkephalinergic inhibitory interneurons situated in substatntia gelatinosa in dorsal horn of spinal cord.