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: Pathology
Hirschsprung colon is due to 
Select and explain. 
A. Muscle atrophy in muscularis mucosa, B. Loss of intrinsic enteric plexuses, C. Loss of extrinsic nerve supply, D. None
B: Loss of intrinsic enteric plexuses
Answer: B: Loss of intrinsic enteric plexuses 
Explanation: Hirschsprung's Disease (Congenital Megacolon) The term 'megacolon' is used for any form of marked dilatation of the entire colon or its segment may occur as a congenital or acquired disorder. Congenital form: congenital absence of ganglion cells in the bowel wall (enteric neurons) is called Hirschsprung's disease. As a result, the aganglionic segment remains contracted. Gross: shows 2 segments, a distal narrow segment that is aganglionic and a dilated proximal segment that contains normal number of ganglion cells Microscopy: distal narrow segment shows total absence of all the three plexus( Auerbach's, Here's, and Meissner's plexus) TEXTBOOK OF PATHOLOGY 6TH EDITION HARSH MOHAN PAGE NO:580 IMAGE REFERENCE: