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30 Cards in this Set
- Front
- Back
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1st _______ weeks important for cranio-facial development |
eight |
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Normal gestationDuration: ___ +/- 2 weeks = full term____ days from first day of last menstrualperiod (LMP) or_____ days from ovulation. |
40; 280 days; 266 days |
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Which trimesters are these? _______ trimester: growth in weight, preparation for birth _______ trimester: from single cell to baby-looking ________ trimester: growth in length, organogenesis |
third; first; second |
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How long are each trimesters (in weeks)? |
First trimester (~0-14 wks): from singlecell to baby-looking Second trimester (~15-27 wks): growth inlength, organogenesis Third trimester (~28 wks to term): growthin weight, preparation for birth |
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Which trimester is the most critical period for normal development? |
The first trimester NOTE: 30% of conceptions end in spontaneous abortions |
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Why is the first trimester is the mostcritical period for normal development? (3) |
1) chromosomal abnormalities 2) abnormal sperm/ oocyte 3) improper implantation ALSO; women know they're pregnant ~2 months, so they may drink and smoke week (everyday) |
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T/F: During the first trimester, theembryo (1st 8 weeks) and fetus (8-14 weeks) are most sensitive to teratogens,including: alcohol, drugs (prescription andrecreational), cigarette smoke, elevated body temperature(hot tubs, maternal fever). |
True! |
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T/F: Paternal age is not linked with schizophrenia. |
False; father's age is linked due to increase rate of random mutations |
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What's Down Syndrome? How does it occur? |
DS= trisomy of chromosome 21 It occurs due to non-disjunction during meiosis NOTE- non-disjunction is when apair of chromosomes doesn’t split off, resulting in an unequal # of chromosomes(gametes are supposed to be haploid) |
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1) _______: sperm + oocyte = embryo 2) _______: via cell division/cleavage, from singlecell to multicellular hollow ball. 3) _______:separating the embryonic region from the extraembryonic components (e.g.placenta) and making intimate contact with maternal tissue. 4) _______: formation of the 3 germ layers -- endoderm, mesoderm and ectoderm via cellmigrations. 5) _______: formation of the brain and spinal cord fromthe ectoderm.Week4: Gut tube formation:from the endoderm, via cranial/caudal and bilateral body folding. 6) _______: Mesoderm development:migration to form muscle, skeleton, dermis, urogenital tract, circulatorysystem, blood and heart. |
Time Zero 1) Fertilization 2) Blastocyst Formation 3) Embryonic Dis and Implantation 4) Gastrulation 5) Neurulation 6) Gut Tube Formation 7) Mesoderm Development Week 4 Each step (Except Fertilization) takes 1 week |
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Blastocyst Formation: What is it? What week? |
Week 1; cell division/ cleavagne, from single cell to multicellular hollow ball |
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Fertilization: What is it? What week? Where does it occur? |
Time Zero; sperm+ oocyte= embryo Occurs: the ampullary portion of the fallopian tube |
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During what trimester stage can embryonic stem cells be deliberately differentiated? |
Blastocyst Stage (when embryo hatches) |
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T/F: Cleavage is cell division accompanied by cell growth |
False; it is not |
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Cleavage is the first next important step after fertilization. When and at what rate does it occur? |
• First cleavage occurs at ~24 hr postfertilization, producing the first 2 blastomeres. • Subsequent cell divisions every 12 hrsproduce the ~30 blastomeres of the morula. |
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The blastocyst forms from the______ via a process of compaction and is fluid filled.Then the blastocyst separates into2 sets of cells: ______ and _______. |
morula; trophoblast and inner cell mass |
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________: becomes the embryo proper and some extraembryonic tissues derives from the small collection of internal blastocyst cells ________: givesrise to the placenta, but not the embryo. derivesfrom the outer cells which become flat and make tight junctions |
•Inner cell mass •Trophoblast |
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Hatching of the Blastocyst: The blastocyst emerges from the __________ 5days after fertilization. At this time, the inner cell mass is abilaminar disc, comprising the _____ and _______. |
zona pellucida epiblast and hypoblast |
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T/F: Hatching is required for implantation of the blastocyst in the endometrial wall in week 2. |
True! |
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How many days after fertilization does implantation occur? |
4-6 days after fertilization, theblastocyst reaches the uterus, which is primed for implantation. |
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Embryonic Disc and Implantation: What is is and what week does it occur? |
Week 2 separatingthe embryonic region from the extra-embryonic components (e.g. placenta) andmaking intimate contact with maternal tissue. |
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Describe the how the bilayered disc forms |
Theinner cell mass becomes bilayered,comprising the outer epiblast layer and the inner hypoblast layer, surroundedby the trophoblast epithelium NOTE: innercell mass= 2 layer structure |
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Bilayered Disc Formation: •The______ and _______ produce extraembryonic tissues, while the ______ gives rise mostly to the embryo proper. |
Trophoblast and Hypoblast epiblast |
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The dorsal _________ is the normal zone for implantation. Theembryo first attaches to, then invades the ___________, with the epiblastalways oriented first toward the uterine wall. _________ cells (from the trophoblast) secrete proteolytic enzymes, allowing the_________ to enter the endometrial wall |
Endometrium Endometrium Syncytiotrophoblast; blastocyst |
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Theinner cell mass which has formed into the bilaminar embryo (______ and _______) and the large fluid-filled space(_________). |
epiblast and hypoblast; blastocoel |
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What three things happens during implantation? |
1) syncytiotrophoblasts generate lacunae (w/in endometrium) which fuses w/ other maternal capillaries (joins maternal/ embryonic cirulation) 2) The amniotic cavity forms around epiblast cells 3) Definitive yolk sac forms the hypoblast |
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Is the hypoblast considered the extraembryonic mesoderm? |
yes |
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What does the primitive yolk sac (aka embryonic umbilical vesicle) forms? |
the umbilical trunk |
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90% of Ectopic Pregnancies are ________, and danger isfrom rupture and subsequent hemorrhage |
tubal |
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LEFT OFF ON SLIDE 25 |
LEFT OFF ON SLIDE 25 |
