Hae - Embryology Quiz 1

Front 1

When is an embryo referred to as a fetus? Why?

Back 1

After 8 weeks b/c organoogenesis is complete.

Front 2

Zygote

Back 2

Fertilized Cell

Front 3

Blastomeres

Back 3

Daughter cells that form after fertilization usually 16-32

Front 4

Morula

Back 4

Collection of blastomeres

Front 5

Where is the ovum fertilized? Where does it go after fertilization?

Back 5

Ovum fertilized in ampulla of uterine tube

Travels to the uterus after fertilization

Front 6

Blastocyst Cavity

Back 6

Fluid-filled area found in the morula

Front 7

Blastocyst

Back 7

Term that refers to a morula w/a blastocyst cavity

Front 8

Outer Cell Layer/Trophoblast

Back 8

Gives rise to embryonic part of placenta and is in blastocyst

Front 9

Inner Cell Layer/Embryoblast

Back 9

Gives rise to whole embryo/embryo proper, forms in blastocyst

Front 10

Embryonic Pole

Back 10

Designated side of the blastocyst where the inner cell mass/embryoplast moves

Front 11

Zona Pellucida

Back 11

Outer protective layer of the blastocyst lost during dev't

Allows rapid growth to occur

Front 12

Outer Syncytiotrophoblast

Back 12

One of the trophoblast differentiated layers, invades uterine wall, produces HCG

Front 13

Inner Cytotrophoblast

Back 13

One of the trophoblast differentiated layers, produces new cells

Front 14

Hypoblast

Back 14

Cell layer that forms after the first week along the embryoblast facing the blastocyst, below epiblast, cells produce extra-embyronic mesoderm

Front 15

Ovum

Back 15

Fertilized Oocyte

Front 16

What are the 2 layers that the inner cell mass becomes?

Back 16

1. Epiblast

2. Hypoblast

Front 17

Epiblast

Back 17

One of layers formed from the inner cell mass, above hypoblast, gives rise to the fetus

Front 18

Bilaminar Germ (Embryonic) Disc

Back 18

Made of the epiblast and hypoblast

Front 19

Amniotic Cavity

Back 19

Cavity that forms within the epiblast, filled with amniotic fluid, lined with amnioblasts (specialized epiblast cells)

Front 20

What ruptures signaling the onset of labor?

Back 20

Amniotic cavity

Front 21

Primary Yolk Sac

Back 21

Below hypoblast layer, contains fluid

Front 22

Extraembryonic Mesoderm

Back 22

Loose connective tissue outside the primary yolk sac, vesicles form here

Front 23

Extraembryonic Coelom

Back 23

Separates the extraembryonic mesoderm into two layers:

1. Extraembryonic splachnic mesoderm
2. Extraembyronic somatic mesoderm

Front 24

Where do the epiblast and hypoblast come from?

Back 24

Inner cell mass/embyroblast

Front 25

What is the bilaminar germ disc comprised of?

Back 25

Epiblast and hypoblast

Front 26

What cavity forms in the epiblast?

Back 26

Amniotic cavity filled with amniotic fluid

Front 27

Cells from what layer give rise to the extraembyonic mesoderm?

Back 27

Hypoblast

Front 28

What is another name for the primary yolk sac?

Back 28

Exocoelomic cavity

Front 29

What is the difference b/w the exocoelomic cavity and the extraembyronic coelom?

Back 29

Exocoelomic cavity = primary yolk sac

Extraembryonic coelom = formed from the extraembryonic mesoderm and separates the mesoderm

Front 30

Chorionic Cavity

Back 30

Renamed term for extraembryonic coelum

Enlarges to pinch off primary sac to give rise to the 2ndary yolk sac

Front 31

Oropharyngeal Membrane

Back 31

Future mouth, forms at end of bilaminar disc where epiblast + hypoblast cells become attached

Front 32

Cloacal Membrane

Back 32

Future anus, forms at end of bilaminar disc where epiblast + hypoblast cells become attached

Front 33

Primitive Streak

Back 33

At the caudal (posterior) end of bilaminar disc, depression is called primitive groove

Front 34

Primitive Node

Back 34

At the cranial (anterior) end of bilaminar disc, depression is called primitive pit

Front 35

Gastrulation

Back 35

Epiblast cells migrate through the primitive groove and pit into area underneath (ventral), displacing existing hypoblast cells to form new hypoblast layer (embryonic endoderm)

Front 36

Embryonic Endoderm

Back 36

Formed during gastrulation when epiblast cells move ventrally from primitive groove and pit

Front 37

Intraembryonic Mesoderm

Back 37

Eventually forms notochord, between the epiblast and hypoblast layers during gastrulation

Front 38

Embryonic Ectoderm

Back 38

Cells that stay in the epiblast during gastrulation

Front 39

How is the notochordal process initiated?

Back 39

Cells migrate from the epiblast through the primitive pit and move in a cranial (anterior) direction in the mesodermal layer until it reaches the oropharyngeal membrane

Front 40

____ will form into the notochord?

Back 40

Notochordal process

Front 41

How is the neural plate formed?

Back 41

Formation of notochord induces the overlying ectoderm to thicken leading to formation of the neural plate

Front 42

Formation of the neural plate leads to formation of a specialized ectoderm referred to as?

Back 42

Neuroectoderm

Front 43

Neurulation

Back 43

Formation of the neural plate, folding of plate into neural folds and closure of folds to form the neural tube

Front 44

Neural Tube

Back 44

Forms during neurulation, gives rise to the CNS

Front 45

Hypoblast cells form what layer?

Back 45

Embyronic endoderm

Front 46

Oropharyngeal Membrane

Back 46

Cranial/Anterior end during gastrulation, future mouth

Front 47

Cloacal Membrane

Back 47

Caudal/Posterior end during gastrulation, future anus

Front 48

Which layer does the notochord arise from?

Back 48

Intraembryonic mesoderm

Front 49

The intraembyronic mesoderm differentiates into which 3 layers?

Back 49

1. Paraxial Mesoderm
2. Intermediate Mesoderm
3. Lateral Plate Mesoderm

Front 50

Intermediate mesoderm gives rise to?

Back 50

Urogenital system

Front 51

Lateral plate mesoderm is involved in what?

Back 51

Body Folding

Front 52

How are somites formed?

Back 52

By paraxial mesoderm differentiation + segmentation

Front 53

Sclerotome

Back 53

Portion of somite, gives rise to bone and cartilage (forming vertebrae + ribs)

Front 54

After the neural tube is formed, what happens?

Back 54

The tube drops beneath the ectodermal layer, closure of the cranial neuropore and then caudal neuropore in a zipper-like fashion

Front 55

Neural Crest Cells

Back 55

Along edge of neural folds, detach themselves and migrate to body areas

Front 56

What does the 2ndary yolk sac become?

Back 56

GI tract + derivatives

Front 57

Lateral plate mesoderm divides into which 2 layers?

Back 57

1. Somatic/parietal layer lining future body wall
2. Splanchnic/visceral layer lining outside of 2ndary yolk sac

Front 58

GI tract is derived from which structure?

Back 58

Yolk sac