Embryology weeks 1-4

Question 1

Pre-embryonic period

Answer 1

Period during which implantation occurs

Question 2

Embryonic period

Answer 2

Period during which major organ systems are formed

Question 3

Fetal period

Answer 3

Period characterized by growth

Question 4

When is the pre-embryonic period?

Answer 4

Weeks 1-2

Question 5

When is the embryonic period?

Answer 5

Weeks 3-8

Question 6

When is the fetal period?

Answer 6

Weeks 9-38

Question 7

When is the embryo most susceptible to teratogens?

Answer 7

Embryonic period

Question 8

When is embryo not sensitive to teratogens?

Answer 8

Pre-embryonic period

Question 9

Where does fertilization normally occur?

Answer 9

Ampulla (neck) of uterine tube

Question 10

What must the sperm penetrate to fertilize the oocyte?

Answer 10

Zona pellucida

Question 11

What is a zygote?

Answer 11

Sperm and egg

Question 12

Rapid mitotic cell division without increasing in size

Answer 12

cleavage

Question 13

How long for an egg to travel the length of the uterine tube?

Answer 13

5 days

Question 14

Layer of cells surrounding the oocyte

Answer 14

Corona radiata

Question 15

First phase of fertilization

Answer 15

Sperm penetrates corona radiata

Question 16

Second phase of fertilization

Answer 16

Sperm penetrates zona pellucida

Question 17

Glycoprotein coat that facilitates binding of sperm

Answer 17

Zona pellucida

Question 18

Which layer blocks fertilization by multiple sperm?

Answer 18

Zona pellucida

Question 19

Third phase of fertilization

Answer 19

Germ cell membranes fuse, triggering completion of meiosis by the ovum

Question 20

How many cells must be present for the developing embryo to be a morula?

Answer 20

16

Question 21

Two groups that morula separates it cells into

Answer 21

Trophoblast cells (outer layer of cavity) and embryoblast (inner cells)

Question 22

Embryo with a hole in the middle

Answer 22

Blastocyst

Question 23

What allows blastocyst to implant on uterine lining?

Answer 23

Enzymatic degradation of the zona pellucida

Question 24

Two layers that the embryoblast differentiates into

Answer 24

epiblast and hypoblast

Question 25

Two layers of the trophoblast

Answer 25

cytotrophoblast and syncytiotrophoblast

Question 26

Cytotrophoblast

Answer 26

contains actively dividing cells

Question 27

Syncytiotrophoblast

Answer 27

layer that invades maternal capillaries

Question 28

hormone produced by syncytiotrophoblasts

Answer 28

human chorionic gonadotrophin (hCG)

Question 29

Structure epiblast cells surround

Answer 29

amniotic cavity

Question 30

Structure hypoblast cells surround

Answer 30

yolk sac

Question 31

What does embryo exist as at the end of week 2?

Answer 31

Bilaminar (two layered) disc

Question 32

Which cell type (epi or hypoblast) becomes dorsal?

Answer 32

Epiblast

Question 33

Process of forming three embryonic germ layers and body axes of embryo

Answer 33

gastrulation

Question 34

Groove at caudal end of epiblast that establishes 3 axes of embryo

Answer 34

primitive streak

Question 35

Raised area at the cranial end of the streak

Answer 35

Primitive node

Question 36

Germ layer created between the epiblast and hypoblast

Answer 36

Mesoderm

Question 37

Germ layer created by migrating epiblast cells replacing hypoblast

Answer 37

Endoderm

Question 38

Germ layer created by cells remaining at the epiblast

Answer 38

Ectoderm

Question 39

Structure that induces development of the nervous system and parts of vertebral column

Answer 39

Notochord

Question 40

One site of epiblast and hypoblast juncture (future mouth)

Answer 40

oropharyngeal membrane

Question 41

One site of epiblast and hypoblast juncture (future anus)

Answer 41

Cloacal membrane

Question 42

In neurulation what does notochord induces overlying ectoderm to become?

Answer 42

Neural plate

Question 43

What does the neural plate close off to become?

Answer 43

Neural tube

Question 44

Where does the neural tube first fuse?

Answer 44

The midregion of the embryo

Question 45

Structures from the surface ectoderm (2)

Answer 45

epidermis of skin and glands

Question 46

Structures from the neural tube (2)

Answer 46

brain and spinal cord

Question 47

Structures from the neural crest cells (2)

Answer 47

Peripheral nervous system and bones of the face

Question 48

Three columns of mesoderm from medial to lateral

Answer 48

paraxial mesoderm, intermediate mesoder, and lateral plate

Question 49

Two layers the lateral plate separates into

Answer 49

Visceral and somatic layer

Question 50

Cells that blood cells develop from

Answer 50

hemangioblasts

Question 51

What are the four places hemangioblasts arise from youngest to oldest

Answer 51

Yolk sac, liver, spleen, bone marrow

Question 52

What causes longitudinal folding?

Answer 52

Rapid growth of brain

Question 53

What does the yolk sac eventually become?

Answer 53

The GI tract/gut tube

Question 54

three regions of the gut tube

Answer 54

foregut, midgut, hindgut

Question 55

Which column of mesoderm differentiates into somites?

Answer 55

Paraxial

Question 56

Which column of mesoderm forms urogenital system?

Answer 56

Intermediate

Question 57

Which column of mesoderm forms limb bones, heart, and blood vessels?

Answer 57

Lateral