Fertilization through gastrulation, the three germ layers, and their tissue derivatives, one fact per card.
About this set
34 basic cards for USMLE Step 1 Embryology. Set 4 of 11 in USMLE Embryology. It opens with "Fertilization normally occurs in the ____ of the uterine (fallopian) tube" and "What reaction alters the zona pellucida immediately after fertilization to". Study it alongside the other USMLE Step 1 sets below.
34 cards · basic cards · AI-written, checked twice. Edit anything.
- Fertilization normally occurs in the ____ of the uterine (fallopian) tube.
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ampulla- What reaction alters the zona pellucida immediately after fertilization to block additional sperm from entering the oocyte?
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The cortical (zona) reaction.- What is the chromosome number of a normal human zygote?
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46, diploid (2N).- What term describes the rapid mitotic divisions of the zygote that occur without an overall increase in size?
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Cleavage.- What solid ball of blastomeres results from cleavage?
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The morula.- Around what day after fertilization does the morula enter the uterine cavity?
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Day 3 to 4.- What is the fluid-filled cavity that forms inside the morula, converting it into a blastocyst?
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The blastocele (blastocyst cavity).- Which outer cell layer of the blastocyst gives rise to the placenta?
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The trophoblast.- Which cluster of cells inside the blastocyst gives rise to the embryo proper?
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The inner cell mass (embryoblast).- Around what day after fertilization does implantation of the blastocyst into the endometrium occur?
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Day 6.- Into which two layers does the trophoblast differentiate?
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Cytotrophoblast and syncytiotrophoblast.- Which trophoblast layer is mitotically active and retains distinct cell boundaries?
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The cytotrophoblast.- Which trophoblast layer is invasive, lacks distinct cell boundaries, and secretes hCG?
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The syncytiotrophoblast.- hCG secreted by the syncytiotrophoblast maintains which ovarian structure during early pregnancy?
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The corpus luteum.- During week 2, the inner cell mass reorganizes into a bilaminar germ disc made of which two layers?
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Epiblast and hypoblast.
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