Question

Arrange the terms given below in their order of occurrence describing their structure and function in the early development of the human embryo Implantation; cleavage; inner cells mass; trophoblast; blastomeres; endometrium; morula; blastocyst.

Answer 1

Correct order = cleavage, blastomeres, morula, blastocyst, trophoblast, inner cell mass/ endometrium, implantation 

Cleavage: mitotic divisions starts as the zygote move through the oviduct towards the uterus and form (2/4/8/16) daughter cells called blastomeres. Embryo with 8 to 16 blastomeres is called a morula. Morula continues to divide and transforms into a blastocyst. Blastomeres in 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 laver then gets attached to the endometrium and inner cell mass differentiates as the embryo. Ultimately blastocyst becomes embedded in the endometrium of uterus. This is called Implantation.