Embryology 2

Question 1

What happens during week 3?

Answer 1

Question 2

How is the primitive streak formed?

Answer 2

Formed in the midline of the epiblast by the dipping in of cells (invagination)

Question 3

What is formed after the primitve streak is formed?

Answer 3

The axis of the embryo is formed

Question 4

Where do epiblast layers migrate to?

Answer 4

Space between epiblast and the hypoblast layers, cells then displace the hypoblast

Question 5

From the original epiblast, what three layers are formed?

Answer 5

Question 6

What are the names of this TRILAMINAR disk?

Answer 6

Question 7

What is gastrulation?

Answer 7

Formation of three germ layers

Question 8

Ectoderm - blue

Mesoderm - red

Endoderm - ?

Answer 8

Yellow

Question 9

What layer does the primitive streak form from?

Answer 9

Ectoderm

Question 10

What is the name given to the solid tube of cells formed from the ectoderm called?

Answer 10

The notochord

Question 11

What induces the ectodermal cells in the midline to form a neural tube?

Answer 11

The notochord

Question 12

What is the precursor for the neural tube?

Answer 12

The neural plate

Question 13

What is neurulation?

Answer 13

Question 14

What is the effect of the neural tube on the mesoderm?

Answer 14

Causes the mesoderm to thicken

Question 15

What happens after the mesoderm thickens?

Answer 15

It splits into three parts

Question 16

What is the name of the three parts of the mesoderm?

Answer 16

Question 17

What happens to the lateral plate of the mesoderm?

Answer 17

Lateral plate mesoderm splits to form a somatic and splanchnic mesoderm

Space formed in between: intraembryonic coelom

Question 18

What does your paraxial mesoderm form?

Answer 18

Somites

Question 19

What does the intermediate plate mesoderm form?

Answer 19

Urogenital system (kidneys + repro)

Question 20

What does the lateral plate form

Answer 20

Body cavity and coverings. Peritoneum, pleura, and body cavities

Question 21

Segmentation of paraxial mesoderm forms?

Answer 21

Somites

Question 22

What does each paraxial mesoderm divide into?

Answer 22

1. Dermatome
2. Myotome
3. Sclerotome

Question 23

What is the function of each of these divisions of the somites?

Answer 23

Question 24

What happens during 4th – 8th weeks – Embryonic period / Organogenetic period?

Answer 24

Question 25

Which lateral plate is on the inside when the lateral folding of the embryo has been completed?

Answer 25

The splanchnic

Question 26

What do the somatic mesoderm and the splanchnic mesoderm form?

Answer 26

Pleura - somatic = Parietal - Splanchnic = Visceral

Question 27

Look

Answer 27

Question 28

Summary of the three germ layers

Answer 28

Question 29

Label the above structures

Answer 29

Question 30

What are teratogens?

Answer 30

Environmental factors that cause abnormal development.

Question 31

What is congenital rubella caused by?

Answer 31

Contraction of german measles when pregnant

Question 32

What are the environmetnal teratogens?

Answer 32

Question 33

What are the genetic factors?

Answer 33

Question 34

Which weeks have a high risk of death, low risk of teratogens?

Answer 34

Weeks 1 and 2

Question 35

Which weeks show a decreasing sensitivity to teratogens?

Answer 35

Weeks 9 - 38

Question 36

Which weeks whow a eriod of the greatest sensitivity to teratogens?

Answer 36

Weeks 3-8

Question 37

What does the risk of a teratogen depend on?

Answer 37

Question 38

How are prenatal diagnosis of malformations made?

Answer 38

Question 39

How are postnatal diagnosis of malformations made?

Answer 39