Wiki Trilaminar Embryo

Question 0

The epiblast invaginates towards the hypoblast to become what three layers?

Answer 0

Ectoderm, mesoderm, endoderm.

Question 1

When does the primitive groove start developing?

Answer 1

15 days.

Question 2

What does fibroblast growth factor 8 do?

Answer 2

made by primitive groove, cell migration and specification,
makes Nodal which maintains primitive groove
regulates Brachyury which controls mesoderm specification

Question 3

Mesodermal cells migrate cranially from the primitive pit to create the _________, which stops at the prechordal plate.

Answer 3

notochordal canal.

Question 4

The prechordal plate (endoderm) and the ectoderm on top fuse to make the __.

Answer 4

oropharyngeal membrane.

Question 5

Some cells migrate from the sides of the notochordal process around the prechordal plate to form

Answer 5

the cardiogenic area.

Question 6

The endoderm and ectoterm at the caudal end of the primitive groove is known as the ________, which is the future site of the ____.

Answer 6

cloacal membrane,

anus.

Question 7

A small diverticulum in the yolk sac near the cloacal membrane is called the _______ (day 16). this is the future _____.

Answer 7

allantois,

urinary bladder, umbilical arteries and veins.

Question 8

Prenotochordal cells and endoderm intercalate to form the

Answer 8

notochordal plate.

Question 9

while endoderm is pushing away hypoblast, the notochordal plate cells detach from endoderm to become

Answer 9

notochord.

Question 10

What does the notochord do?

Answer 10

basis of axial skeleton
future site of vertebral bodies,
primary inducer of embryo. tells ectoderm above it to become neural plate.

Question 11

The neural plate lateral edges fold upward and fuse at 21 days at the ___ somite.

Answer 11

5th

Question 12

After the neural tube separates from the ectoderm, the ectoderm becomes ____.

Answer 12

epidermis of skin

Question 13

Neural crest cells undergo _____ transition as they leave the closed neuroectoderm.

Answer 13

epithelial to mesenchymal.

Question 14

Neural cells from the trunk region of neuroectoderm have two pathways, dorsal and ventral. name cell fates of these pathways.

Answer 14

dorsal: melanocytes
ventral: dorsal root ganglion, sympathetic/enteric neurons, autonomic ganglia, schwann cells adrenal medulla cells

Question 15

Neural crest from cranial neural plate become

Answer 15

craniofacial skeleton, neurons of cranial ganglia, melanocytes etc.

Question 16

Which closes first, the cranial or caudal neural fold?

Answer 16

cranial. No close caudal is spine ebifida.

Question 17

What are the three layers of mesoderm?

Answer 17

Paraxial,
intermediate,
lateral

Question 18

An intraembryonic coelom divides the lateral mesoderm into 2 layers

Answer 18

Somatic mesoderm,

splanchnic mesoderm.

Question 19

What does the intermediate mesoderm become? Which structures?

Answer 19

Urogenital system:
gonads, ducts, accessory glands. reproductive urinary structures (ureters, vas deferens) parts of kidneys
nephrogenic cords, nephrotome

Question 20

What does the somatic mesoderm form?

Answer 20

skin, bone, connective tissue and muscle of limbs.

Question 21

what does splanchnic mesoderm form?

Answer 21

gut tube.

Question 22

Somitomeres form in the paraxial mesoderm. From the occipital region caudally, somitomeres will organize into ___.

Answer 22

Somites.

Question 23

42-44 somites. ___ occipital. ___ cervical. ___ thoracic. _____ lumbar. ___ sacral. ___ coccygeal.

Answer 23

4 occipital. 
8 cervical. 
12 thoracic. 
5 lumbar
5 sacral
8-10 coccygeal. 
first occipital and 5-7 coccygeal disappear.