Question

Peritoneum and thyroid gland originate respectively from which of the following germ layers?

• A. Mesoderm and endoderm
• B. Endoderm and mesoderm
• C. Endoderm and endoderm
• D. Ectoderm and mesoderm

Answer 1

The correct option is A Mesoderm and endoderm

The germ layers represent the three different cell types that will continue to differentiate during development to give rise to the more than 200 different types of cells that make up a human. The endoderm lineage represents the inner-most layer of cells following gastrulation. These cells are the first to migrate through the primitive streak and the adult cells that they will give rise to include those that will make up the gut, the liver, and the lungs. The epithelium and glands of digestive tract; epithelium of lower respiratory tract and urinary bladder; glandular epithelium of thyroid, parathyroid, pancreas and thymus; epithelium of vagina and accessory sex structures are all derived from endoderm.
The cells that migrate into the embryo later and that position themselves between the endoderm and surface layer become the mesoderm. The adult cells that the mesoderm will give rise to include those that will make up the peritoneum; skeleton and skeletal muscle; the heart; the blood and the kidneys.