Embryology: 2nd Week of Development

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What differentiates into two layers over the embryoblast on day 8?

  • Syncytiotrophoblast
  • Trophoblast (correct)
  • Endometrial stroma
  • Cytotrophoblast

What type of cells form the outer layer of the trophoblast on day 8?

  • Syncytiotrophoblast (correct)
  • Cytotrophoblast
  • Multinucleated zone without clear cell boundaries
  • Mononucleated cells

What is formed by the cells of the inner cell mass or embryoblast on day 8?

  • Endometrial stroma
  • Bilaminar embryonic disc
  • Blastocyst cavity
  • Hypoblast and epiblast layer (correct)

What appears within the epiblast on day 8?

<p>Small cavity (B)</p> Signup and view all the answers

Where is the blastocyst partially embedded on day 8?

<p>Endometrial stroma (A)</p> Signup and view all the answers

Describe the structure of the blastocyst on day 8 of development.

<p>The blastocyst on day 8 of development consists of a trophoblast partially embedded in the endometrial stroma, with the inner layer differentiating into cytotrophoblast and syncytiotrophoblast, and the embryoblast forming a bilaminar embryonic disc with epiblast and hypoblast layers.</p> Signup and view all the answers

Explain the differentiation of the trophoblast on day 8.

<p>On day 8, the trophoblast differentiates into two layers: the inner layer forms cytotrophoblast with mononucleated cells, and the outer layer forms syncytiotrophoblast with multinucleated zone without clear cell boundaries.</p> Signup and view all the answers

Discuss the development of the embryoblast on day 8.

<p>On day 8, the cells of the inner cell mass or embryoblast differentiate into two layers: hypoblast consisting of small high cuboidal cells near the blastocyst cavity, and epiblast forming a flat disc with columnar cells near the amniotic cavity.</p> Signup and view all the answers

What is the significance of the small cavity appearing within the epiblast on day 8?

<p>The small cavity appearing within the epiblast on day 8 contributes to the formation of the bilaminar embryonic disc, consisting of epiblast and hypoblast layers, which is essential for further embryonic development.</p> Signup and view all the answers

Explain the process of cell migration within the trophoblast on day 8.

<p>On day 8, the cells in the cytotrophoblast divide and migrate into the syncytiotrophoblast, forming multinucleated zone without clear cell boundaries within the outer layer of the trophoblast.</p> Signup and view all the answers

Flashcards

Syncytiotrophoblast

Outer layer of trophoblast; multinucleated zone

Cytotrophoblast

Inner layer, mononucleated cells

Day 8: Two-Layer Formation

Embryoblast differentiates into two layers

Hypoblast

Small high cuboidal cells near the blastocyst cavity

Signup and view all the flashcards

Epiblast

Flat disc with columnar cells near the amniotic cavity

Signup and view all the flashcards

Amniotic Cavity (Early)

Cavity that appears within the epiblast

Signup and view all the flashcards

Trophoblast Differentiation

Differentiates into cytotrophoblast and syncytiotrophoblast

Signup and view all the flashcards

Cytotrophoblast Cells

Migrate into the syncytiotrophoblast

Signup and view all the flashcards

Blastocyst on Day 8

Has a trophoblast partially embedded

Signup and view all the flashcards

Embryoblast

The inner cell mass become the hypoblast and epiblast layer

Signup and view all the flashcards

Study Notes

  • The second week of development (Bilaminar germ disc) is the focus of this lecture.
  • The blastocyst, a fluid-filled structure, is partially embedded in the endometrial stroma on Day 8.
  • The trophoblast layer of the blastocyst differentiates into two layers: an outer layer (syncytio trophoblast) and an inner layer (cyto trophoblast). The outer layer has multinucleated cells, while the inner layer has mononucleated cells.
  • Cells of the inner cell mass or embryoblast differentiate into two layers: the epiblast and hypoblast. The epiblast forms the embryyonic disc and has small, high, cuboidal, and columnar cells, while the hypoblast forms the extraembryonic membranes.
  • A small cavity appears within the epiblast on Day 8, leading to the formation of the blastocyst cavity. The two layers then form a flat disc called the bilaminar embryonic disc.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser