Question

In which stage of development the embryonic cells form the germinal layers?

• A. Morula
• B. Blastula
• C. Gastrula
• D. None of the above

Answer 1

Answer: (C)

Gastrula

Gastrulation is the formation of three distinct germ layers ectoderm (outer layer), mesoderm (middle layer) and endoderm (inner layer) in the early embryo from the inner cell mass of the blastocyst after it is implanted in the uterine wall which later on forms the gastrula.The ectoderm forms the nervous system, the epithelial cells of the mammary glands, the lens of the eyes, hair and the epidermis of the skin. The mesoderm forms skeletal muscle, smooth muscle, the heart, blood vessels and most of the urogenital system. The endoderm forms the epithelial lining of the gastrointestinal tract, the liver, pancreas, thyroid and the respiratory system.

Thus the correct answer is option C.