Early Embryonic Developement

Question 1

look at embryos to…

Answer 1

-describe the evolution of life and how different animals form their organs

Question 2

veterinarian interest

Answer 2

common abnormalities

• missing limbs
• missing/extra digits
• cleft palate

Question 3

teratogen definition

Answer 3

any agent or facotr that can cause congenital anomalies in a embryo or fetus

Question 4

teratogen factors

Answer 4

• genetic factors
• radiation
• hormones
• chemical agents
• infectious agents: viruses, parasites

Question 5

tertogenic influences on development

Answer 5

• at predifferentiation: embryo dies
• organogenesis: structural defects
• fetal growth: affects functional maturation

Question 6

zygote

Answer 6

single cell, large

Question 7

morula

Answer 7

compact mass of cells,

Question 8

blastula

Answer 8

fluid-filled cyst with cells at periphery,

Question 9

early gastrula

Answer 9

bilaminar disk

Question 10

late gastrula

Answer 10

trilaminar disk to tube shape

Question 11

order of cell devolpement

Answer 11

zygote,morula, blastula, early gastrula, late gastrula

Question 12

four basic tissues

Answer 12

epithelium, connective tissue, muscle, nervous tissue

Question 13

Cleavage: Morula

Answer 13

16 cells, ‘mulberry’, zona pellucida still intact, late morula has 32 cells

Question 14

Cleavage: Blastocyst

Answer 14

cavity begins to form, outer cell mass (trophoblast) and inner cell mass (embryoblast) present. no overall change in size from zygote-‘compaction’–>zona pellucida is shed shortly-‘hatching’ of blastula–>expanded blastocyst

Question 15

Cleavage: gastrula

Answer 15

formation of 3 germ layers & primitive axial organs: neural tube, notochord, somites, and primitive gut

Question 16

blastogenesis

Answer 16

compaction occurs as cell division occurs, no increase on overall size of embryo while inside zona pellucida

Question 17

trophoblast

Answer 17

will form part of placental membranes

Question 18

inner cell mass

Answer 18

embryoblast: will form entire embryo, forms bilaminar disc of epiblast and hypoblast; establishes dorsal and ventral axis

Question 19

ectoderm

Answer 19

derived from epiblasts

form: epithelium, nervous tissue, and neural crest cells

Question 20

mesoderm

Answer 20

connective tissue, muscle, enothelium, mesothelium, urogenital system

Question 21

endoderm

Answer 21

epithelium of digestive and respiratory systems

-derived from hhypoblas

Question 22

epithelium derived from

Answer 22

all three layers

Question 23

gastrulation

Answer 23

formation of 3-layered embryo, begins with the formation of the primitive streak in epiblast

Question 24

ectoderm

Answer 24

formed by epiblast cells that migrated toward primitive streak

Question 25

primary endoderm

Answer 25

formed by the replacement of hypoblast/endoblast cells, also lines the yolk sac

Question 26

mesoderm

Answer 26

formed from cells migrating from primitive streak

Question 27

notochord

Answer 27

cluster of cells derived from mesoderm, determines axis of embryo and required to signal neural tube formation from neuroectoderm

Question 28

mesoderm inductive effects:

Answer 28

1. forms notochord
2. notochord induces ectoderm to form neural tissue
3. neural tube and neural crest cells formed
4. some somites seen
5. lateral, cranial. caudal body folds create head, tail, primitive anus and mouth
6. nervous system defines

Question 29

neural tube formation

Answer 29

1. neural ectoderm thickens
2. neural folds dip down producing the neural groove
3. neural folds contact, neural ectoderm cells rearrange
4. form the neural tube with overlying

Question 30

parts of mesoderm

Answer 30

1. axial: notochord
2. paraxial: somites
3. intermediate: urinary/gential
4. lateral plate

Question 31

somites

Answer 31

division of animal’s body giving rise to muscle, cartilage, tendons, dermis, limbs, vertebrae

• dermatome: dermis
• myotome: skeletal muscle
• sclerotome: cartilage,tendons,endothelia, forms axial skeleton

Question 32

cranial part of neural tube

Answer 32

brain, in skull

Question 33

caudal part of neural tube

Answer 33

spinal cord, will be in vertebral (neural) canal of the back bone

Question 34

neural crest cells

Answer 34

transient, multipotent, migratory cell population unique to vertebrates that give rise to a diverse cell lineage including melanocytes, craniofacial cartilage and bone