Development of blastocyst Flashcards
Why is there only one polar body in a mature oocyte?
Because the oocyte is arrested after its first meiotic division so sperm entry activates the second meiotic division.
What do the further polar bodies formed from 2nd meiotic division contain?
Extraneous genetic material that arise during meiosis that isn’t required.
What is the function of polar bodies?
To ensure the oocyte remains haploid until the pronuclei combine.
What is the first stage of division after the formation of the pronuclei
Cleavage division
What is the second stage after the formation of the pronuclei?
Morula
How many cells is a morula?
16! (cleavage then 2 then 4 then 8 then morula)
Describe the difference between pregnancy and development?
Pregnancy is timed from first day of the last day of the last menstrual period (40weeks) whereas development is from fertilisation (38wks)
After how many days does the pre-embryo hatch from the zone pellucida to allow implantation
5 days
What cells make up a blastocyst?
Blastomere cells
State the two types of blastomere cells
Inner mass and trophoblast cells
What do inner mast cells develop into?
Fetus
What do trophoblast cells develop into?
Placenta
