#mostimp POINTS #NCERT Cleavage and Implantation • The mitot | NCERT PCMB OFFICIAL ™✅
#mostimp POINTS #NCERT
Cleavage and Implantation
• The mitotic division starts as the zygote moves through the isthmus of the oviduct called cleavage towards the uterus and forms daughter cells called blastomeres.
• Morula: The embryo with 8 to 16 blastomeres.
• The blastomeres in the blastocyst are arranged into an outer layer called trophoblast and an inner group of cells attached to trophoblast called the inner cell mass.
• The trophoblast layer attached to the endometrium and the inner cell mass gets differentiated as the embryo.
• After attachment, the uterine cells divide rapidly and cover the blastocyst. As a result, the blastocyst becomes embedded in the endometrium of the uterus. This is called implantation.
• Implantation leads to pregnancy.
• Amnion is innermost embryonic membrane and never participates in placenta formation.
• Chorion is outermost embryonic membrane and always participates in placental formation.
