Image Based Question-65185

Which of the following is NOT true concerning the structure marked as “B” in the picture below?

A. It is a mucocutaneous junction joining the embryonic hindgut and the proctodeum.

B. The columnar epithelium of the rectum is replaced at the level of the dentate line.

C. The anal canal below the dentate contains the columns of Morgagni.

D. Distal to the dentate the anus is lined with stratified squamous epithelium.

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Correct Answer » C Explanation

Ans;C. Anal canal below dentate contains the column of Morgagni.

The structure marked as “B” in the picture above represents the dentate line of the anal canal.

The rectum contains columnar epithelium and this is replaced by a transition zone in the upper anus, consisting of a combination of columnar and squamous epithelium.

This is the area that corresponds with the embryonic fusion of the hindgut and the proctodeum. The dentate line is the junction at the level of the anal valves.

Above the dentate line lies the columns of Morgagni which end in the anal valves. Caudal to the dentate line the anus is lined by only stratified squamous epithelium.