Embryology 2 Flashcards
What happens during week 3?
How is the primitive streak formed?
Formed in the midline of the epiblast by the dipping in of cells (invagination)
What is formed after the primitve streak is formed?
The axis of the embryo is formed
Where do epiblast layers migrate to?
Space between epiblast and the hypoblast layers, cells then displace the hypoblast
From the original epiblast, what three layers are formed?
What are the names of this TRILAMINAR disk?
What is gastrulation?
Formation of three germ layers
Ectoderm - blue
Mesoderm - red
Endoderm - ?
Yellow
What layer does the primitive streak form from?
Ectoderm
What is the name given to the solid tube of cells formed from the ectoderm called?
The notochord
What induces the ectodermal cells in the midline to form a neural tube?
The notochord
What is the precursor for the neural tube?
The neural plate
What is neurulation?
What is the effect of the neural tube on the mesoderm?
Causes the mesoderm to thicken
What happens after the mesoderm thickens?
It splits into three parts
What is the name of the three parts of the mesoderm?
What happens to the lateral plate of the mesoderm?
Lateral plate mesoderm splits to form a somatic and splanchnic mesoderm
Space formed in between: intraembryonic coelom
What does your paraxial mesoderm form?
Somites
What does the intermediate plate mesoderm form?
Urogenital system (kidneys + repro)
What does the lateral plate form
Body cavity and coverings. Peritoneum, pleura, and body cavities
Segmentation of paraxial mesoderm forms?
Somites
What does each paraxial mesoderm divide into?
- Dermatome
- Myotome
- Sclerotome
What is the function of each of these divisions of the somites?
What happens during 4th – 8th weeks – Embryonic period / Organogenetic period?
Which lateral plate is on the inside when the lateral folding of the embryo has been completed?
The splanchnic
What do the somatic mesoderm and the splanchnic mesoderm form?
Pleura - somatic = Parietal
- Splanchnic = Visceral
Look
Summary of the three germ layers
Label the above structures
What are teratogens?
Environmental factors that cause abnormal development.
What is congenital rubella caused by?
Contraction of german measles when pregnant
What are the environmetnal teratogens?
What are the genetic factors?
Which weeks have a high risk of death, low risk of teratogens?
Weeks 1 and 2
Which weeks show a decreasing sensitivity to teratogens?
Weeks 9 - 38
Which weeks whow a eriod of the greatest sensitivity to teratogens?
Weeks 3-8
What does the risk of a teratogen depend on?
How are prenatal diagnosis of malformations made?
How are postnatal diagnosis of malformations made?
