Week 2: Difference between revisions
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==Week 2 Abnormalities== | |||
===Monoygotic Twinning=== | |||
Monozygotic twins (identical) produced from a single [[F#fertilization|fertilization]] event (one fertilised egg and a single spermatazoa, form a single zygote), these twins therefore share the same genetic makeup. Occurs in approximately 3-5 per 1000 pregnancies, more commonly with aged mothers. The later the twinning event, the less common are initially separate placental membranes and finally resulting in conjoined twins. | |||
{| class="prettytable" 100% | |||
| width=10% | '''Week''' | |||
| | |||
| colspan="7" | Week 1 | |||
| colspan="7" | Week 2 | |||
|-bgcolor="lightsteelblue" | |||
| '''Day''' | |||
| width=5% | 0 | |||
| width=5% | 1 | |||
| width=5% | 2 | |||
| width=5% | 3 | |||
| width=5% | 4 | |||
| width=5% | 5 | |||
| width=5% | 6 | |||
| width=5% | 7 | |||
| width=5% | 8 | |||
| width=5% | 9 | |||
| width=5% | 10 | |||
| width=5% | 11 | |||
| width=5% | 12 | |||
| width=5% | 13 | |||
| width=5% | 14 | |||
|- | |||
| '''Cell Number''' | |||
| 1 | |||
| 1 | |||
| 2 | |||
| 16 | |||
| 32 | |||
| 128 | |||
| | |||
| | |||
| | |||
| bilaminar | |||
| | |||
| | |||
| | |||
| | |||
| | |||
|- | |||
| '''Event''' | |||
| Ovulation | |||
| fertilization | |||
| First cell division | |||
| Morula | |||
| Early blastocyst | |||
| Late blastocyst | |||
Hatching | |||
| Implantation starts | |||
| | |||
| | |||
| X inactivation | |||
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|- | |||
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| [[File:Follicle 001 icon.jpg|50px]] | |||
| [[File:Early_zygote.jpg|50px]] | |||
| [[File:Human embryo day 2.jpg|50px]] | |||
| [[File:Human embryo day 3.jpg|50px]] | |||
| [[File:Human embryo day 5.jpg|50px]] | |||
| [[File:CSt3.jpg|50px]] | |||
| [[File:Week2_001 icon.jpg|50px]] | |||
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|-bgcolor="lightsteelblue" | |||
| '''Monoygotic''' | |||
'''Twin Type''' | |||
| | |||
| colspan="3" | Diamniotic | |||
Dichorionic | |||
| colspan="3" | Diamniotic | |||
Monochorionic | |||
| colspan="3" | Monoamniotic | |||
Monochorionic | |||
| colspan="5" | Conjoined | |||
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|} | |||
Table based upon: Twinning. Hall JG. Lancet. 2003 Aug 30;362(9385):735-43. Review. [http://www.ncbi.nlm.nih.gov/pubmed/12957099 PMID: 12957099] | |||
{{Template:Week}} | {{Template:Week}} |
Revision as of 09:32, 15 June 2010
Introduction
Key events of human development during the second week (week 2) following fertilization or Clinical week 4 (LMP).
Links: 2009 Lecture - Week 2
Event | ||
Implantation | ||
Stage 6 | Chorionic Cavity | |
Week 2 and 3 Movies
Implantation | Mesoderm | Chorionic Cavity | Amniotic Cavity | Week 3 |
Week 2 Abnormalities
Monoygotic Twinning
Monozygotic twins (identical) produced from a single fertilization event (one fertilised egg and a single spermatazoa, form a single zygote), these twins therefore share the same genetic makeup. Occurs in approximately 3-5 per 1000 pregnancies, more commonly with aged mothers. The later the twinning event, the less common are initially separate placental membranes and finally resulting in conjoined twins.
Table based upon: Twinning. Hall JG. Lancet. 2003 Aug 30;362(9385):735-43. Review. PMID: 12957099
Embryo Week: Week 1 | Week 2 | Week 3 | Week 4 | Week 5 | Week 6 | Week 7 | Week 8 | Week 9
- Carnegie Stages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | About Stages | Timeline
Glossary Links
- Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link
Cite this page: Hill, M.A. (2024, June 16) Embryology Week 2. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Week_2
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G