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Question
Morula is a developmental stage
Morula is a developmental stage
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Solution
The correct option is A between the zygote and blastocyst
The haploid nucleus of sperm and ovum fuse to form a single-celled diploid zygote. The division starts as the zygote moves through the isthmus part of the oviduct. The process by which the zygote divides is called cleavage. It is a special kind of mitosis, where the number of cells keeps on increasing in the same cytoplasmic mass until implantation. By the process of this cell division, the single-celled zygote converts into a multicellular structure called blastula at the end of the first week of fertilization. Cleavage in the fertilized egg starts in the fallopian tube forming 2, 4, 8, 16 daughter cells called blastomeres. In this stage of an embryo, where the number of blastomeres inside the zona pellucida layer is 8-16 is known as morula. The stage of cell division where the embryo becomes 64 celled, a cavity is formed within the cell mass, i.e. blastocoel inside is known as the blastocyst. Where the cells on the periphery are called trophoblast which gets attached to the endometrium during implantation and the clumped cells attached to the periphery from inside are called inner cell mass.
The formation of the morula is a stage between the single-celled zygote and the blastocyst. Gastrulation is the process of formation of gastrula from blastula. In this process, the inner cells of the blastocysts rearrange into a three germ layered structure forming ectoderm, mesoderm and endoderm. From these germ layers organ formation will occur later in embryos.
Figure: Stages of embryo development
The haploid nucleus of sperm and ovum fuse to form a single-celled diploid zygote. The division starts as the zygote moves through the isthmus part of the oviduct. The process by which the zygote divides is called cleavage. It is a special kind of mitosis, where the number of cells keeps on increasing in the same cytoplasmic mass until implantation. By the process of this cell division, the single-celled zygote converts into a multicellular structure called blastula at the end of the first week of fertilization. Cleavage in the fertilized egg starts in the fallopian tube forming 2, 4, 8, 16 daughter cells called blastomeres. In this stage of an embryo, where the number of blastomeres inside the zona pellucida layer is 8-16 is known as morula. The stage of cell division where the embryo becomes 64 celled, a cavity is formed within the cell mass, i.e. blastocoel inside is known as the blastocyst. Where the cells on the periphery are called trophoblast which gets attached to the endometrium during implantation and the clumped cells attached to the periphery from inside are called inner cell mass.
The formation of the morula is a stage between the single-celled zygote and the blastocyst. Gastrulation is the process of formation of gastrula from blastula. In this process, the inner cells of the blastocysts rearrange into a three germ layered structure forming ectoderm, mesoderm and endoderm. From these germ layers organ formation will occur later in embryos.
Figure: Stages of embryo developmentSuggest Corrections
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