Cleavage Flashcards
Cleavage forms from_____ to _____
Day 1-5
Patterns of cleavage
1.) Poles
2.) Cleavage pattern divisions (1-5)
3.) Cleavage patterns yolk
4.) Timing of cleavage pattern
Cleavage humans
1.) Recap
2.) At 8-cell stage (morula)
3.) Morula by day 4
4.) Blastocyst by day 5
Principles of cleavage
1.) Now 1 cell: initial phase of cell division after fertilization (within 24 hours)
2.) New established combination of DNA, complete set of genetic information
3.) Rapid series of mitotic cell divisions and cells form daughter blastomeres
4.) Cell is “cleaved” or “cut up” into smaller cells (within Zona Pellucida)
5.) Cleavage produces cells of a geometric progression
6.) Morula (solid ball)
Cell is “cleaved” into smaller cells within the ________
Zona pellucida
Nucleocytoplasmic reaction (“cleaved”)
- specific ratio of nucleus to cytoplasm
- SAME overall size but the cell divides
Cleavage geometric progression
- 2 cells
- 4 cells
- 8 cells
- 16 cells
- 32 cells
(hard to follow 32 cells)
Morula
- solid, ball-like structure
- up to 32 cells “raspberry”
- same size as original egg
Morula (16-32 cells) is also known as_______
“raspberry”
Timeline
- Time 0: sperm + egg (zygote)
- 24 hours: 2 cells
- 40 hours: 4 cells
- 3 days: 6-12 cells
- 4 days: 16-32 cells (morula)
egg + sperm –> fertilization –> zygote
true
1st mitotic divisions are called_______ and results in _____ daughter cells
cleavage; 2 (2n)
Blastomeres
smaller than original cell, daughter cells
Morula
embryo at 16-32 cell stage
– blast
immature cell (actively making something)
– cyte
mature cell
– cyst
sac full of fluid
ESC
Embryonic Stem Cells from inner cell mass (ICM) of blastocyst
Pluripotent
ESC that can become any one of the 3 germ line cells
Differentiate
Cell than can alter into another specific cell
Embryo
After zygote and into 1st cell divisions, from implantation through 8th week pregnancy
Fetus
after 9 weeks of fertilization 11 weeks gestation
Holo
entire or complete
Mero
part