Zygote is an egg cell which has been fertilised with a spermatozoon. This spilt into two cells know as cleavage.
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How long does it take for a zygote to start dividing
12-24 hours after ovulation
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Where does the spematozoon and ovum meet
In the uterus, more specifically the ampulla. The ampulla is near to the ovaries in the fallopian tube.
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What is a Morula ?
Morula- When the mitosis occurs (cleavage) and the ovum divides into 16 cells.
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What is compaction?
When the cells in the morula becomes closer together. This forms two types of cells: embryoblast and the trophoplast. This happens in the first wekk.
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Where is the embryoblast found and in what week?
The embryoblast is found week 1 and it is the inner cell mass.
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Where is the trophoplast found and in what week?
The trophoplast is found week 1 and it is the outer cell mass.
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What is blastulation and when does it occur?
Blastulation is the formation of a blastocyst from the morula. This happens in week 2.
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What happens in blastulation part 1?
The embryoblast clump together at the top of the cell forming a inner cell mass. This forms a cavity known as the blastocyst cavity (blastocoel). The zona pellucida disintegrates. The morula has now become a blastocyst.
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What happens in blastulation part 2?
The inner cell mass forms a cavity called the amniotic cavity. The bottom cells have differentiated, and now the higher layer is called the epiblast, and the lower layer is called the hypoblast
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What happens in blastulation part 3?
The hypoblast cells line the blastocyst to form a primary yolk sac
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What is a bilaminar disc?
This is the evolution of the embryoblast to the epiblast and hypoblast.
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When is the connection stalk Connecting stalk –(primitive umbilical cord)
Week 2 during blastrulation
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Tell me about uteroplacental circulation
By third week diffusion can no longer supply needs of the developing embryo. Formation of primitive blood vessels
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When does gastrulation occur?
In week 3
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What happens in gastrulation?
The primitive streak is a site where epiblast cells begin to migrate into the hypoblast. This forms three new layer: ectoderm, mesoderm and endoderm. The epiblast became the ectoderm and the hypoblast became the endoderm.
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Where is the epiblast?
This happens in blastulation. It is part of the bilaminar disc and it is on top of the hypoblast.
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Where is the hypoblast ?
This happens in blastulation. It is part of the bilaminar disc and it is on top of the hypoblast.
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When does blastulation occur?
In week 2
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What is the trilaminar disc?
This happens in gastrulation. There is three layers: ectoderm, mesoderm and endoderm.
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What is the notochord?
The notochord is a core which is underneath the primilative streak. It is part of the mesoderm.
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What does the notochord do?
Causes the area in the ectoderm to become thicker causing a neural plate.
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How is the neural tubed formed?
The neural plate start to divide causing a neural tube. The process causes small cells in the ectoderm to break off and go into the mesoderm.
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Organogenesis occurs in what week
occurs in the 3-8 months
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What happens in Organogenesis
The trilaminar disc differentiates into different specific tissues
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How are muscles formed in organogenesis
The mesoderm slides downwards creating somites
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What is embryo folding
The embryo folds so the heart can start to form and can beat.
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How long does it take for a zygote to start dividing
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