This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Medicine
The defect in achalasia cardia is present in 
Select and explain. 
A. Myenteric plexus of Auerbach, B. Meissner's plexus, C. Kesselbach's plexus, D. Mesenteric plexus
A: Myenteric plexus of Auerbach
Answer: A: Myenteric plexus of Auerbach 
Explanation: Achalasia is characterized by impaired esophageal body peristalsis and incomplete lower esophageal sphincter relaxation. It is a rare disease caused by loss of ganglion cells within the esophageal myenteric plexus usually presenting between age 25 and 60. With longstanding disease, aganglionosis is noted. The disease involves both excitatory (cholinergic) and inhibitory (nitric oxide) ganglionic neurons. Functionally, inhibitory neurons mediate deglutitive lower esophageal sphincter (LES) relaxation and the sequential propagation of peristalsisRef: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 347 Diseases of the Esophagus; Page no: 1904