Question

The buccopharyngeal membrane is formed by the junction of which two embryonic layers?

• A. Foregut ectoderm and oral endoderm
• B. Oral ectoderm and foregut endoderm
• C. Neural ectoderm and foregut endoderm
• D. Oral ectoderm and hindgut endoderm

Hint:

Buccopharyngeal membrane = Oral ectoderm + Foregut endoderm with no intervening mesoderm.

Answer 1

The Correct Option is B

Step 1: Understanding the Buccopharyngeal Membrane.
The buccopharyngeal membrane, also called the oropharyngeal membrane, is an early embryological structureIt marks the boundary between the primitive mouth (stomodeum) and the foregutThis membrane eventually ruptures to establish communication between the oral cavity and the pharynx
Step 2: Embryological Composition.
The primitive mouth (stomodeum) is lined by ectodermThe foregut is lined by endodermAt the site of the buccopharyngeal membrane, these two germ layers come into direct contact without any intervening mesodermThus, the membrane is formed by oral ectoderm externally and foregut endoderm internally
Step 3: Evaluation of Options.
(A) Foregut ectoderm and oral endoderm: IncorrectForegut is lined by endoderm, not ectoderm
(B) Oral ectoderm and foregut endoderm: CorrectThis accurately describes the two germ layers forming the buccopharyngeal membrane
(C) Neural ectoderm and foregut endoderm: Neural ectoderm forms neural structures, not this membrane
(D) Oral ectoderm and hindgut endoderm: Hindgut is unrelated to the buccopharyngeal membrane
Step 4: Conclusion.
Therefore, the buccopharyngeal membrane is formed by the junction of oral ectoderm and foregut endoderm