9.28 Fertilization Flashcards
the ability of cells to form the syncytiotrophoblast is due to an ancient viral protein called ________
syncytin
Problems with ________ are a common cause of female infertility since they are needed to move the egg down the tube
cilia function
_________ twins occur when there are two ovulations, two fertilizations, and two implantations
dizygotic
what is the slow block for polyspermy?
Slow block - cortical reaction. space between egg membrane and zone pellucida - perivitelline space. Enzymes secreted here
upon fusion of the sperm with the oocyte membrane, the second meiosis is ___________ and one set of maternal chromosomes is expelled into a second ___________.
completed
polar body
what is the fast block to block polyspermy?
Fast block - change in membrane potential among initial binding that prevents further sperm fusion events
the __________ is a part of the trophoblast with one nucleus per cell.
cytotrophoblast
after fertilization, the zygote undergoes cell divisions, making a 8-16 still stage called the ______ stage, where cells are _______ with each other (not too strongly though)
morula
associated
the ___________ digests through the uterine wall, surrounding the ___________ during invasion. Eventually, the ___________ will cover the whole embryo once buried in the uterine wall.
syncytiotrophoblast
cytotrophoblast
syncytiotrophoblast
implantations of the zygote anywhere but the uterus. Usually in tube, but sometimes in body cavity
ectopic pregnancies
A group of trophoblast cells close to the inner cell mass form the _____________ – multinuclear cells that lead to invasion of the uterine wall
syncytiotrophoblast
If uterine tube becomes ______ or ______, it could prevent access of sperm to egg, or movement of the egg to the uterus.
scarred or inflamed
what is the space called between the ovum membrane and zona pellucida during the cortical reaction?
perivitelline space
attachment of _______________ cells to the uterine wall begins implantation. this is mediated by _______ on the cell surface of the invading cells.
syncytiotrophoblast
L-selectin
glycoproteins surrounding the sperm head are removed in a process called _______
capacitation
cells forming the outer layer of the blastocyst will form the _______
trophoblast
the stage in which the cells form a sphere around a fluid filled space is called the:
blastula
around __-__ days after fertilization, implantation occurs
5-6
At around 100 cells, there is a division into the ________ and _______ cell mass. The inner cell mass becomes the _______ and the outer layers will make the _________ layer.
inner, outer cell mass
embryo
trophoblast
the sperm must cross the __________ (granulosa cells attached to ovum) and __________ (inner glycoprotein layer) of the egg in order to contact the oocyte membrane. It does this through _________ enzymes released from the sperm tip.
corona radiata
zona pellucida
acrosomal
___________ twins can be due to splitting to zygote during blastula stage.
monozygotic
___________ twins can be due to formation of two separate inner cell masses
monozygotic
The egg with a 1n nucleus and a polar body. Not fertilized, is called the _______.
ovum
the making of the perivitelline space is called the _______________.
cortical reaction
A fertilized egg. The fusion between the male and female pronucleus to form a diploid nucleus.
What is this structure not called?
zygote
