Preimplantation, Emryonic, Fetal

Question 1

Embryonic stage:

Answer 1

Day 4- 8 weeks

Question 2

Fetal stage:

Answer 2

8 weeks- birth

Question 3

Chromosomal #

Mitosis-

Meiosis-

Answer 3

Mitosis- 1 parents cells divides and creates 2 daughter cells with same genetic complement.
*Diploid

Meiosis- creates daughter cells with half the # of chromosomes compared to the parent cell.
*Haploid

Question 4

Preimplantation:

Fertilization-

Zygote-

Answer 4

Union of sperm and ovum

Newly formed cell with diploid # of chromosomes
*different from parent, undergoes meiosis

Question 5

Preimplantation:

Morula-

Blastocyst-

Answer 5

Solid mass of cells

Fluid filled collection of cells

Question 6

Embryonic period:

Blastocyst to embryo stage-

Answer 6

From 2nd to 8th week

Question 7

Embryonic period:

Cytodifferentation- what are the 2 types

Answer 7

Receptors

Processes

Question 8

Cytodifferentation receptors:

None present-

Couple receptors-

More receptors-

Still more receptors-

Answer 8

Cells will die

Couple receptors

Cells proliferate

Cells differentiate

Question 9

Cytodifferentation processes:

Autocrine-

Paracrine-

Answer 9

Cell receives hormone or receptor stimulation from a substance produced by itself

cell receives hormone or receptor stimulation from a substance produced by a different cell

Question 10

Preimplantation stage:

Answer 10

4-7 days

Question 11

Types of growth:
Aptosis-
Induction-

Answer 11

Programmed cell death.
*babies have webbed hands before birth. Aptosis kills those cells and cause fingers.

1 group of cells starting development of another cellular group.

Question 12

Types of growth:

Proliferation-

Interstitial-

Appositional-

Answer 12

More cells (a lot of)

Additional outer layers of cells *outside ball

occurs deep within a tissue *inside ball

Question 13

Differentiation:

Histodifferentiation-

Morphodifferentiation-

Answer 13

Development of different tissues.

Development of different form = structure or shape

Question 14

Differentiation:

Morphogenesis-

Maturation-

Answer 14

Process where tissues evolve into more complex structures. *shape very specific (complex) ex-enamel

Ongoing physiological processes which impacts the final form/function.

Question 15

Second week:

Blaminar embryonic disc-

Amniotic cavity-

Answer 15

Forms directly from the blastocyst
*epiblast layer, hypoblast layer

Fluid filled

Question 16

Second week:

Yolk sac-

Trophoblastic layer-

Answer 16

Provides nourishment until placenta is established.

Outer layer, highly invasive layer

Question 17

Layer order:

Answer 17

Blastocyst 
Bilaminer
Amniotic cavity
Epiblast 
Hypoblast
Yolk sac 
Trophoblastic

Question 18

Third week:

Mesenchymal cells-

Answer 18

Formed from migration of epiblast.
*Complete migration=trilaminar disc

Epiblast to ectoderm
Mesenchymal to mesoderm
Hypoblast to endoderm

Question 19

Third week:

Primitive streak

Answer 19

From proliferation of ectoderm at the mid-line or the disc

Question 20

Neural crest cells:

Neural crest cells-

Trilaminar embryonic disc-

Answer 20

Arise from proliferation of ectoderm adjacent to primitive streak

Primitive streak matures into notocord who supports the primitive embryo

Question 21

Third week:

Ectoderm-

Answer 21

Skin, CNS & PNS, hair, nails, enamel, and lining of oral cavity

Question 22

Third week:

Mesoderm-

Answer 22

Bone, muscles, circulatory and reproductive systems, internal organs, Dentin, pulp, and cementum.

Question 23

Third week:

Endoderm-

Answer 23

Lining of respiratory passages, glandular organs, and digestive system.

Question 24

Fourth week:

Embryonic folding-

Answer 24

Will cause endoderm to become the deepest tissue. Ectoderm will be most superficial tissue.

Question 25

Fourth week:

Orientation of tissues-
*2 layers
Buccopharyngeal-
cloacal-

Answer 25

Disc is now tubular in shape. Only 2 membranes have only 2 tissue layers: buccopharyngeal and cloacal

Buccopharyngeal- will become the primitive mouth
Cloacal- will become the anus

Question 26

Fourth week:

Neural tube development-

Answer 26

Anterior end- gives rise to brain
*anacephlia

Posterior end- gives rise to the spinal cord
*spinabifida

Question 27

Teratogens:

What is it and what causes it(4)?

Answer 27

Problems in development, interacts with differentiation *making of a monster

1. Infectious disease (rubes,German measles)
2. X-radiation
3. Drugs
4. Nutritional deficiencies

Question 28

General steps in development (3)

Answer 28

1. Initiation *start –> simple mitosis
2. Proliferation
3. Differentiation *different types of tissues

Question 29

Stomodeum or stomatodeum (3)

Answer 29

1. Primitive mouth
2. Disintegration-oropharyngeal membrane joins primitive mouth and primitive pharynx
3. Will give rise to the mouth

Question 30

Dentin pulp and cementum come from what layer in 3rd week?

Answer 30

Mesoderm

Question 31

Enamel and the oral cavity come from what layer 3rd week?

Answer 31

Ectoderm