Question

A baby failed to pass meconium. In this disease, the structures absent are absent in which of the following layer(s)?

Select the correct answer from the given below cord:

• A. 1 n 2
• B. 2 n 3
• C. 3 n 4
• D. 1 n 4

Hint:

Hirschsprung = absent ganglion cells of Meissner's (submucosa) and Auerbach's (muscularis) plexuses → layers 2 and 3.

Answer 1

The Correct Option is B

Step 1: Identify the disease. A neonate who fails to pass meconium has Hirschsprung disease (congenital aganglionic megacolon). It results from failure of neural crest cells to migrate to the distal bowel, so the affected segment lacks ganglion cells of the enteric nervous system, causing a functional obstruction (failure to pass meconium).

Step 2: Locate the missing structures. The "structures absent" are the ganglion cells / nerve plexuses of the enteric nervous system. There are two such plexuses in the bowel wall:
• The submucosal (Meissner's) plexus - located in the submucosa (layer 2).
• The myenteric (Auerbach's) plexus - located in the muscularis, between the inner circular and outer longitudinal muscle layers (the muscular layer, layer 3).

So the ganglion cells are absent from the submucosal and muscular layers - i.e. layers 2 and 3.

Step 3: Map to the options. Layer 1 = Epithelial (mucosa), Layer 2 = Submucosa, Layer 3 = Muscular, Layer 4 = Serosa. The plexuses lie in the submucosa (2) and muscularis (3), so the correct combination is 2 and 3.

Step 4: Why the others are wrong. The epithelium (1) is a lining layer with no enteric ganglia, and the serosa (4) is the outer covering with no plexus; therefore any combination including 1 or 4 is incorrect.

Final answer: Option B - 2 n 3 (submucosa and muscular layers).