Preimplantation, Emryonic, Fetal Flashcards Preview

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Flashcards in Preimplantation, Emryonic, Fetal Deck (31)
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1

Embryonic stage:

Day 4- 8 weeks

2

Fetal stage:

8 weeks- birth

3

Chromosomal #

Mitosis-

Meiosis-

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

4

Preimplantation:

Fertilization-

Zygote-

Union of sperm and ovum

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

5

Preimplantation:

Morula-

Blastocyst-

Solid mass of cells

Fluid filled collection of cells

6

Embryonic period:

Blastocyst to embryo stage-

From 2nd to 8th week

7

Embryonic period:

Cytodifferentation- what are the 2 types

Receptors

Processes

8

Cytodifferentation receptors:

None present-

Couple receptors-

More receptors-

Still more receptors-

Cells will die

Couple receptors

Cells proliferate

Cells differentiate

9

Cytodifferentation processes:

Autocrine-

Paracrine-

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

10

Preimplantation stage:

4-7 days

11

Types of growth:
Aptosis-
Induction-

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.

12

Types of growth:

Proliferation-

Interstitial-

Appositional-

More cells (a lot of)

Additional outer layers of cells *outside ball

occurs deep within a tissue *inside ball

13

Differentiation:

Histodifferentiation-

Morphodifferentiation-

Development of different tissues.

Development of different form = structure or shape

14

Differentiation:

Morphogenesis-

Maturation-

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

Ongoing physiological processes which impacts the final form/function.

15

Second week:

Blaminar embryonic disc-

Amniotic cavity-

Forms directly from the blastocyst
*epiblast layer, hypoblast layer

Fluid filled

16

Second week:

Yolk sac-

Trophoblastic layer-

Provides nourishment until placenta is established.

Outer layer, highly invasive layer

17

Layer order:

Blastocyst
Bilaminer
Amniotic cavity
Epiblast
Hypoblast
Yolk sac
Trophoblastic

18

Third week:

Mesenchymal cells-

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

Epiblast to ectoderm
Mesenchymal to mesoderm
Hypoblast to endoderm

19

Third week:

Primitive streak

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

20

Neural crest cells:

Neural crest cells-

Trilaminar embryonic disc-

Arise from proliferation of ectoderm adjacent to primitive streak

Primitive streak matures into notocord who supports the primitive embryo

21

Third week:

Ectoderm-

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

22

Third week:

Mesoderm-

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

23

Third week:

Endoderm-

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

24

Fourth week:

Embryonic folding-

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

25

Fourth week:

Orientation of tissues-
*2 layers
Buccopharyngeal-
cloacal-

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

26

Fourth week:

Neural tube development-

Anterior end- gives rise to brain
*anacephlia

Posterior end- gives rise to the spinal cord
*spinabifida

27

Teratogens:
What is it and what causes it(4)?

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

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

28

General steps in development (3)

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

29

Stomodeum or stomatodeum (3)

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

30

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

Mesoderm