Term
| Describe the processes involved between fertilization --> blastocyst formation |
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Definition
1. Mature follicle ruptures releasing an ooctye and forming the corpus luteum
2. Oocyte fertilized by sperm (now a zygote)
3. Zygote divides into 2, 4, 8 cells
4. Zygote becomes a morula
5. Morula continues to divide into a blastocyst (trophoblast, inner cell mass, beginning of yolk sack) |
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Term
| On what day does implantation into the uterine wall occur? |
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Definition
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Term
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Definition
A pregnancy in which the blastocyst implants somewhere other then the uterine wall (fallopian tube, cervix, ovaries, etc.)
Note: Fallopian tube is most common location for this |
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Term
| What critical process leads to the formation of identiical twins (as opposed to fraternal) and what determines if they are conjoined or not? |
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Definition
1. Division of the inner cell mass (as opposed to fertilization of 2 separate eggs --> fraternal)
2. Proximity of the divided cell masses. If they are far apart enough to separately cleave, 2 nonjoined twins form, as opposed to if they are too closely located to each other |
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Term
| What are the two layers of the bilaminar embryo? |
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Definition
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Term
| What does the trophoblast differentiate into and what role does it serve? |
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Definition
| It becomes the cytotrophoblast which in turn becomes the syncytiotrophoblast. This layer is invasive and essential in successful implantation into the uterine wall. |
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Term
| Which of the two bilaminar layers gives rise to the 3 essential embryonic germ layers? |
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Definition
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Term
| During what week does gastrulation begin to occur |
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Definition
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Term
| What embryonic structure invaginates and allows migration of cells to form the 3 germ layers? |
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Definition
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Term
| What does the endoderm fold into? What does the ectoderm fold into? |
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Definition
Endoderm --> gut lining
Ectoderm --> neural tube |
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Term
| What role does the notochord play in neural development |
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Definition
| Motoneurons form in the neural tube on the side closer to the notochord (induces the formation of motoneurons, Hensel's frog experiment) |
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