CLEAVAGE

• Cleavage is the mitotic division which starts as the zygote moves through the isthmusof the oviducttowards the uterus and forms2, 4, 8, 16 daughter cells called as blastomeres
• The embryo with 8 to 16 blastomeres is called a morula
• The morula divides further as it moves further in to the uterus and transforms into blastocyst
• Theblastomeres in the blastocyst are arranged in to an outer layer called trophoblast and inner mass of cells attached to trophoblast is called as inner cell mass.
• The trophoblast layer then gets attached to the endometrium of the uterus and the inner cell mass divide to cover the blastocyst hence blastocyst becomes embedded in the endometrium of the uterus and the process is called as implantation.

Fig. blastocyst