Cleavage Stages and Placental Development Flashcards

1
Q

Where does fertilization usually occur?

A

Ampulla

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2
Q

Events of fertilization

A
  1. Corona radiata
  2. Zona pellucida
  3. Zona reaction
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3
Q

Corona radiata

A

layer of cuboidal cells surrounding the egg; sperm enter by secreting proteolytic enzymes

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4
Q

Zona pellucida and cortical reaction

A
  • layer of glycoproteins; acrosome reaction happens where acrosome (cap) over the head of the sperm ruptures and releases digestive enzymes that degrade the glycoproteins
  • When the first sperm penetrates, cortical granules lining the ovum membrane rupture, releasing enzymes like peroxidases (cortical reaction)
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5
Q

Zona reaction

A

release of enzymes in cortical reaction inactivate receptors for spermatozoa binding on the outside of the zone, preventing further sperm from penetrating

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6
Q

Sperm nucleus enters egg cytoplasm and becomes…

A

male pronucleus

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7
Q

Once male pronucleus forms, the egg is now ________ and is called a _______.

A

fertilized; zygote

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8
Q

Once female pronucleus develops, pronuclei drawn together during….via….and then they….

A

first mitotic division via mitotic spindle; membranes break down and intermix

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9
Q

Cells of early embryo…

A

Blastomeres

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10
Q

After 3rd cleavage, 8 cell embryo is called…

A

Morula

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11
Q

Compaction

A

Separation of inner (fetus) and outer (chorion and placenta) cells

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12
Q

After organization of ICM, trophoblast, and blastocoel, embryo known as…

A

Blastocyst

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13
Q

ICM produces…

A

Fetus, yolk sac, and extraembyonic mesoderm

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14
Q

Outer mass fate…

A

trophoblast

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15
Q

Trophoblast produces….

A

extraembyonic layers (cytotrophoblast, synctiotrophoblast)

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16
Q

Hatching

A

Blastocyst prepares for implantation by hatching from zona pellucida

17
Q

Morphogenesis of embryonic circulatory system

A

a. Mesenchymal cells differentiate into angioblasts > primitive RBCs OR endothelial cells to produce capillaries > interconnect to establish embryonic circulatory system

18
Q

Primary villi

A

cytotrophoblast core surrounded by synctiotrophoblast

19
Q

Secondary villi

A

Mesodermal core develops w/i cytotrophoblast

20
Q

Tertiary villi

A

Blood vessels invade mesoderm

21
Q

Once villi invade all the way to endometrium, they form a layer called…

A

Outer trophoblast shell

22
Q

Terminal villi

A

Branch off of stem villi

23
Q

Nutrient exchange b/w fetal and maternal circulation through…

A

Terminal tertiary villi

24
Q

Maternal component of placenta begins with…

A

Trophoblastic lacunae forming in the synctiotrophoblast

25
Q

Maternal sinusoids

A

Expanded trophoblastic lacunae that have coalesced with glands and capillaries in overlying endometrium

26
Q

Overlying endometrium known as…

A

Decidua

27
Q

Where does maternal blood flow?

A

Intervillous space

28
Q

Where does embryonic blood flow?

A

Within vessels in villi