• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/21

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

21 Cards in this Set

  • Front
  • Back
What process occurs in the first two weeks of pregnancy?
Embryogenesis
What are the basic goals of embryogenesis?
• From fertilization to a successful uterine implantation: the development of placental precursors and the embryonic bi-laminar disk
What are the first few steps of embryogenesis?
1. 8th day - blastocyst partially embedded in the uterine wall

2. Syntrophoblasts continue to invade the uterine wall

3. Form a Fibrin Plug (a woman can spot at her normal cycle time, but its not a real period

4. Differentiation of (embryoblast) embryonic disc into 2 layers:
• Epiblast
• Hypoblast
1. Epiblast?

2. Hypoblast
1. A COLUMNAR cell layer facing the cytotrophoblast (closest to the cavity)

2. A CUBOIDAL cell layer facing the blastocyst cavity (outside the epiblast)
Amniotic Cavity
Space between the epiblast and the cytotrophoblast
Amnioblasts
• Formed from the cytotrophoblasts

• Line the upper region of the amniotic cavity
What do cytotrophoblasts form?
• amnioblasts and Heuser's membrane

• extraembryonic mesoderm
What is Heuser's Membrane?
Membrane that surrounds the original blastocyst cavity. Now the cavity is called the Primary Yolk Sac
What does the Blastocyst Cavity become?
The Primary Yolk Sac
The extraembryonic mesoderm is made up of two parts:
• Extraembryonic Somatic Mesoderm

• Extraembryonic Splanchnic Mesoderm
What does the Extraembryonic Somatic Mesoderm line?
Inner surface of the cytrotrophoblast
What is the Chorion?
Formed by the Extraembryonic Somatic Mesoderm and the two layers of trophoblasts
What does the Extraembryonic Splanchnic Mesoderm line?
Lines the trophoblasts (outer surface of the yolk) and covers the amnion
What do Syntrophoblasts do?
• Grow all over and develop spaces called Lacunae

• They eventually establish Uteroplacental Circulation
When does the Extraembryonic Mesoderm form?
Middle of the second week
What are the Maternal Blood Sinusis?
They are filled with the mother's blood and flow into the sytrophoblastic lacunae on the 12th day allowing primitive uteroplacental circulation
What does the primary yolk sac become?
The secondary yolk sac
1) What is the secondary yolk sac lined by?

2) When does the secondary yolk sac form?
1) Heuser's membrane

2) After the extraembryonic membrane and extraembryonic coelom form a cavity
Primary Stem Villi
Extensions of cytotrophoblast that grow out into the blood-filled lacunae (covered by syntrophoblasts)
Cytotrophoblasts give rise to:
1. Amnioblast

2. Heuser's Membrane

3. Extraembryonic Membrane (2 layers, 1 space [extraembryonic coelom])

4. Forms column of cells (primary stem villi)
What are the 3 spaces formed during the second week of development?
1. Amniotic Cavity - spaces between amnioblast and embryoblast

2. Primary Yolk Sac - Blastocyst lined by Heuser's membrane

3. Secondary Yolk Sac - primary yolk sac lined by Heuser's membrane