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
Why does initiation of nerve impulse occurs at the axon hillock? 
Select and explain. 
A. It is unmyelinated, B. Due to the release of neurotransmitter, C. It has a lower threshold than the rest of the axon, D. None of the above
C: It has a lower threshold than the rest of the axon
Answer: C: It has a lower threshold than the rest of the axon 
Explanation: In motor neurons, the poion of the cell with the lowest threshold for the production of a full fledged action potential is the initial segment, the poion of the axon at and just beyond the axon hillock. Ref: Ganong's Review of Medical Physiology, 23rd Edition, Chapter 4.