Exam 1 weeks 2 & 3 Flashcards
On the 8th day what two parts do the blastocyst become?
Embryoblast and Trophoblast
What two layers do the embryoblast become?
Epiblast and Hypoblast
What 2 layers do the trophoblast become?
Cytotrophoblast and Synctiotrophoblast
What releases amnionic fluid into the cavity?
What method is amnionic fluid absorbed?
- Embryo peeing and maternal secretion
- Embryo ingests fluid
Polyhydraminios: ?
Oligohydramnios: ?
Polyhydraminios: excess amnionic fluid.
Oligohydraminos: too little amniontic fluid
What is the name for the inner lining of the primary yolk sac (originally extraembryonic endoderm?
Heuser’s membrane
What are the two layers of extraembryonic mesoderm and what do they form?
Somatopleuric (forms the chorion) and splanchnopleuric (contributes to the umbilical cord)
What does the syncytiotrophoblast secrete, and what differentiates from Cytotrophoblast?
HcG, lose their cell structure, multinucleated blob while cytotrophoblast maintain cell structure.
On day 9 what does uteroplacental strutures form?
Trophoblastic lacunae and the maternal sinusoids
How does the embryo receive nutrients on the first week?
Through simple diffusion
On day 16 extraembryonic mesoderm extends into primary stem villi mak
On day 16-26 how does the embryo receive nutrients?
-Secondary stem villi the mesoderm extends into the primary stem villi.
By the end of 3rd week how does the embryo receive nutrients?
Tertiary stem villi: the villus has formed blood vessels that connect to forming fetal blood vessels.
What layers must material crossing between mother and fetus transverse?
Synciotrophoblast, cytotrophoblast, connective tissue, wall of the blood vessel
What is the chorion (which helps form the placenta) is composed of?
- syncytiotrophoblast
- Cytotrophoblast
- Somatopleuric layer of extrembryonic mesoderm
- What genetic parent donates contributes more to the formation of the trophoblast?
- What genetic parent donates contributes more to the formation of the embryoblast?
- The father
- the mother
What are primary characteristics of hydatidiform Moles?
- secretes high levels of hCG, and growth to big too fast for the gestational age.
What types of moles are poorly developed embryo and always a result of triploid?
Partial moles
What does a complete mole arise from?
- Is the development of the trohoblast without an embryoblast.
What can occur with a mole that is not completely removed lead to?
- a malignancy possible a choriocarcinomas
What day and what event begins gastrulation? How long does it last?
Day 15 the epiblast begins moving cells toward the primitive streak.
- Lasts to week 4
- What is the notochord derived from?
- Where does the length of the notochord go from and to?
Composed of mesoderm and endodermal cells
- Stretches from the primitive pit to the prechordal plate.
What are the functions of the Notochord?
Functions of NotochordHigh Yield
- CNS development
- Development of the vertebral column
- Anatomic midline
- Forms the nucleus pulposis (IV discs)
What is a Neuroenteric Cysts and what are its symptoms?
- The neuroenteric canal is an opening in the ectoderm that allow the notochord to pass through. A neurenteric cyst is the persistence of this primitive streak resulting in a compressive lesion on the spinal column.
What accounts for the head-tail fold that occurs in the sagittal plane?
The rapid growth of the CNS and differential growth.
What is extopia cordis?
Is a thoracic wall defect in which the heart is on the outside of the chest wall.
What is the main result of embryonic folding?
The flat trilaminar embryo becomes a tubular embryo
What are the 2 disorders that could have the heart on the opposite side of the body? What differentiates them?
- Dextracarda (only the heart is on the wrong side)
- Situs inversus (everything is on the wrong side)
What is the disorder in which midline deficiency issues are present? What are the two structures that cause them?
- Holoproencephaly - varying degrees of severity
- Issues with the primitive streak and with the primitive node.
Caudal dysgenesis could result in what defect in amniotic fluid?
oligohydraminous- due to a lack of external genitalia producing amniotic fluid.
What is are distinguishing characteristics of a sacral coccygeal teratoma?
- Tumor at the coccyx (externally on the butt), tumor contains hair, teeth, skin,
