Chapter 3 Week 2 Of Human Debelopment Flashcards Preview

BRS Embryology > Chapter 3 Week 2 Of Human Debelopment > Flashcards

Flashcards in Chapter 3 Week 2 Of Human Debelopment Deck (18):

The embryoblast differentiates in to two distinct cellular layers: the e__________ and the h__________.

Epiblast, hypo last


The epiblast is composed of ( cuboidal / columnar ) cells while the hypoblast is composed of ( cuboidal / columnar ) cells.

Epi - columnar
Hypo - cuboidal


The epiblast and the hypoblast form the b_________ e__________ d_____.

Bilaminar embryonic disk


The epiblast cells form clefts and surround a space called the a_________ c_________.

Amniotic cavity.


Hypoblast cells line the inner c__________ forming the e__________ m___________. The space delimited is called the e_____________ c_________ or p________ y_____ s______.

Cytotrophoblast, exocoelomic membrane, exocoelomic cavity, primitive yolk sac.


When does the primitive yolk sac become the definitive yolk sac?

After the formation of the exocoelomic cyst.


What structure forms at the future site of the mouth? What cell type do both the epiblast and the hypoblast take at this site?

Prochordal plate.
Columnar cells.


The syncytiotrophoblast forms from the c____________. Does the syncytiotrophoblast under go mitosis?

The syncytiotrophoblast does NOT under go mitosis.


Early uteroplacental circulation is established after what event? How does the embryoblast receive nutrition at this time?

The fusion of isolated lacunae in the syncytiotrophoblast to form a lacunae network.
Nutrient are carried to the embryoblast via diffusion.


Is the cytotrophoblast mitotically active?



What are primary chorionic vili, and where do they arise from?

Mounds of cells, they arise from the cytotrophoblast.


The chorionic cavity is surrounded by what two merged layers of tissue?

The extraembryonic somatic mesoderm which lines the cytotrophoblastic layer, and the extraembryonic visceral mesoderm that lines the extracoelomic membrane.


What is hCG, where is it produced?

Human chorionic gonadotropin - a glycoprotein, the syncytiotrophoblast.


What organ is stimulated to produce which hormone by hCG produced by the syncytiotrophoblast?

The ovary, esp. the corpus luteum. hCG stimulates the production of progesterone.


hCG is manufactured by the syncytiotrophoblast through the ______ week of pregnancy after which the p___________ begins to produce hCG.

Eight week, placenta


Which day of pregnancy can hCG be detected in maternal blood; and in maternal urine.

Blood - day 8
Urine - day 10


A decline in hCG may predict which event?

Spontaneous abortion.


What three conditions might an excess of hCG indicate?

1. Multiple pregnancy
2. Hyatidaform mole
3. Gestational trophoblastic neoplasia