Practice question

Initial cleavages increase blastomere number without concomitant growth, as total volume remains constrained by zona pellucida. After three divisions eight-cell stage compacts, fourth cleavage produces sixteen blastomeres forming mulberry-like morula. During morula stage E-cadherin mediated adhesion maximizes cell contact, apicobasal polarity established in outer cells and tight junctions begin forming. Internal cells remain apolar and become ICM progenitors. Morula represents transitional organization between uniform blastomeres and differentiated blastocyst with distinct trophectoderm and inner cell mass lineages preparing for cavitation, hatching and implantation processes.