Question

The amnion of mammalian embryo is derived from

• A. ectoderm and mesoderm
• B. mesoderm and trophoblast
• C. endoderm and mesoderm
• D. ectoderm and endoderm

Answer 1

The Correct Option is A

The amnion is a critical structure in the development of a mammalian embryo. It is a membranous sac that surrounds and protects the embryo. This structure is an example of an extra-embryonic membrane found in amniotes, which include reptiles, birds, and mammals.

The specific layers of the amnion in mammals consist mainly of two types of tissues derived from the embryonic layers:

• Ectoderm: This is the outermost layer of cells or tissue of an embryo in early development.
• Mesoderm: This is the middle layer of an embryo in early development, between the endoderm and ectoderm.

Thus, the amnion is derived from a combination of ectoderm and mesoderm. The ectoderm forms the outer layer of the amnion, while the mesoderm forms the inner layer.

This combination of ectoderm and mesoderm is an essential aspect of the development of this protective sac, which plays a crucial role in providing a stable and nurturing environment for the developing embryo and aids in fluid regulation.

Justification for the Correct Answer:

• The correct answer is: ectoderm and mesoderm.
• This option is correct because both the ectoderm and mesoderm contribute to the formation of the amnion.

Ruling Out Other Options:

• Mesoderm and trophoblast: This option is incorrect because the trophoblast forms the outer layer of the blastocyst and contributes to the placenta, not the amnion.
• Endoderm and mesoderm: This option is incorrect because the endoderm primarily forms internal structures like the digestive tract, not the amnion.
• Ectoderm and endoderm: This option is incorrect because the mesoderm, not the endoderm, is involved in forming the amnion along with the ectoderm.

Therefore, the amnion of a mammalian embryo is derived from ectoderm and mesoderm.