7: Gastrulation And Embryonic Germ Layers

Question 1

What type of oocyte is released at ovulation?

Answer 1

Secondary oocyte

Question 2

Three types of granulosa cells in follicle

Answer 2

Cumulus oophorous, mural granulosa cells, corona radiata

Question 3

Cumulus oophorous

Answer 3

Anchor oocyte to follicle wall

Question 4

Mural granulosa cells

Answer 4

Line wall of follicle

Question 5

Corona radiata

Answer 5

Firmly anchored to ZP, remains around oocyte after fertilization

Question 6

Acrosome reaction

Answer 6

Head of sperm releases enzymes for passage through corona radiata and ZP

Question 7

Zona reaction

Answer 7

Changes in ZP make it impermeable to other sperm once penetrated by one sperm

Question 8

When does cleavage begin?

Answer 8

About 30hrs post-fertilization

Question 9

Compaction

Answer 9

Cells divide but dont grow much in early stages bc they are limited in space by ZP

Question 10

Blastocyst two parts

Answer 10

Trophoblast, embryoblast (AKA inner cell mass)

Question 11

What does the trophoblast differentiate into

Answer 11

Cytotrophoblasts, syncytiotrophoblasts

Question 12

What does embryoblast differentiate into?

Answer 12

Hypoblast, epiblast

Question 13

What layer of cells is the hypoblast continuous with?

Answer 13

Exocoelomic membrane surrounding the exocoelomic cavity

Question 14

What space is the epiblast surrounding?

Answer 14

Amnionic cavity

Question 15

Early spontaneous abortion rate

Answer 15

~45%

Question 16

Two major causes of early spontaneous abortions

Answer 16

Inadequate hormones from the CL; chromosomal abnormalities

Question 17

What two cell layers form the primary umbilical vesicle (yolk sac)?

Answer 17

Hypoblast, exocoelomic membrane

Question 18

What does the primary umbilical vesicle give rise to

Answer 18

Extraembryonic coelom

Question 19

How does the secondary umbilical vesicle form?

Answer 19

Hypoblast cells migrate inside primary umbilical vesicle

Question 20

What type of cells have thier origin in the secondary umbilical vesicle

Answer 20

Primordial germ cells

Question 21

What two types of mesoderm form from the extraembryonic mesoderm, and what separates the mesoderm into these two parts?

Answer 21

Extraembryonic coelom: separates extraembryonic mesoderm -> extraembryonic somatic + splanchnic mesoderm

Question 22

Extraembryonic somatic mesoderm: lines what two things

Answer 22

Trophoblast + amnion

Question 23

Extraembryonic splanchnic mesoderm: surrounds what

Answer 23

Umbilical vesicle

Question 24

Two structures that form the chorionic sac

Answer 24

Extraembryonic somatic mesoderm + trophoblast

Question 25

Chorion

Answer 25

Fetal component of the placenta

Question 26

Where is the most common location for ectopic pregnancies

Answer 26

Oviduct

Question 27

Gastrulation

Answer 27

Epiblast cells migrate to form the primary germ layers

Question 28

What is the starting point of gastrulation

Answer 28

Formation of the primitive streak

Question 29

What germ layer is epithelia from?

Answer 29

All three

Question 30

5 things that come from ectoderm

Answer 30

1. Epidermis and derivatives 2. CNS and PNS 3. NCCs 4. Eyes 5. Internal ears

Question 31

8 things that come from mesoderm

Answer 31

1. Skeletal and smooth muscle 2. Serosal linings 3. Urogenital ducts and organs 4. CV system and blood cells 5. Endothelium 6. Cartilage, bones, tendons, ligaments 7. Dermis 8. Stroma of trunk organs

Question 32

3 Things that come from endoderm

Answer 32

1. GI and resp epithelium 2. GI tract glands 3. Glands of accessory GI organs (liver, pancreas)

Question 33

What germ layer is formed by the notochordal process?

Answer 33

Mesoderm

Question 34

What day is the notochordal process complete by?

Answer 34

Day 20

Question 35

What does the notochordal process extend from -> to?

Answer 35

Primitive node -> prechordal plate

Question 36

What does the notochordal process form?

Answer 36

Notochord

Question 37

Notochord major function

Answer 37

Primary signaling center for early embryo

Question 38

Two things the notochord signals for

Answer 38

1. Formation of neural plate | 2. Development of axial musculoskeleton

Question 39

What does the notochord degenerate into?

Answer 39

Nucleus pulposus

Question 40

In notochord formation, what happens when the floor of the notochord and the endoderm fuse?

Answer 40

The layer degenerate, allowing notochord canal and umbilical vessel to have contact

Question 41

Caudal eminence

Answer 41

Tail bud; a group of median mesodermal cells in the caudal region

Question 42

What forms the caudal eminence?

Answer 42

Swelling of the primitive streak caudally

Question 43

Three cell types formed by the caudal eminence?

Answer 43

Caudal neural tube, NCCs, caudal somites

Question 44

Cell type that forms sacrococcygeal tumors

Answer 44

Primitive streak cells (from any/all germ layers)

Question 45

Population most affected by sacrococcygeal teratomas

Answer 45

Females