This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Physiology
Mass movement of the colon would be abolished by 
Select and explain. 
A. Extrinsic denervation, B. Distension of the colon, C. Gastrocolic reflex, D. Destruction of auerbach's plexus
D: Destruction of auerbach's plexus
Answer: D: Destruction of auerbach's plexus 
Explanation: Mass movements are special type of peristaltic contractions which are observed in colon only. A mass movement can be initiated by Gastrocolic reflex Intense stimulation of parasympathetic nerves Overdistension of a segment of colon Gastrocolic reflex refers to contraction of colon induced by entry of food into the stomach. This reflex results in an urge to defecate after a meal. Gastrocolic reflexes results from distension of stomach & duodenum & these are transmitted by way of autonomic nervous system. Trypanosoma cruzi, a species of parasitic euglenoid protozoan causes destruction of Auerbach&;s plexus in walls of colon which leads to the blockage of both the peristalsis & mass contractions. Therefore, the feces pass with difficulty & get accumulated in large intestine leading to dilatation of colon (megacolon). Reference: Medical Physiology, Indu Khurana