Q.Describe the structure of blastula.
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Start your 14-day free trial to unlock the full solution →The blastula (blastocyst) is a hollow ball made of an outer trophoblast layer surrounding a fluid-filled blastocyst cavity, with an inner cell mass attached to one side.
Step 1. The blastula, in humans called the blastocyst, forms once the solid morula hollows out during blastulation, over about days 4–7 after fertilization.
Step 2. Its outer layer of cells is the trophoblast — flattened cells that absorb glycogen-rich uterine milk, expanding the structure and forming the fluid-filled blastocyst cavity within.
Step 3. The inner, larger cells form the inner cell mass (embryoblast), attached to the trophoblast on only one side; this defines the blastocyst's polarity, with the embryonal end (bearing the inner cell mass) opposite the abembryonal end. …
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