MHT CET Medical202624 April 2026Evening ShiftBiologyHuman ReproductionActual
During early embryonic development in humans, which of the following options shows the correct sequence of the various events given below. I. Formation of hypoblast and epiblast II. Appearance of primitive streak III. Differentiation of cytotrophoblast and syncytiotrophoblast. IV. Formation of amnion
Options
- AIII I IV II
- BII III IV I
- CI III II IV
- DIV I III II
Correct answer
A. III I IV II
Step-by-step solution
During early embryonic development, implantation starts around the 7th to 8th day. The trophoblast first differentiates into two layers: an inner cytotrophoblast and an outer syncytiotrophoblast (III). Around the 8th day, the inner cell mass (embryoblast) differentiates into a bilaminar embryonic disc consisting of two layers: the hypoblast and the epiblast (I). Following this, a small cavity appears within the epiblast, which enlarges to form the amniotic cavity. The epiblast cells adjacent to the cytotrophoblast