Embryogenesis Flashcards
Ampulla
Region of the Fallopian tube where fertilization occurs. It is the widest part of the Fallopian tube.
Acrosomal Apparatus
When the first sperm comes into contact with the oocyte, it releases acrosomal enzymes that enable the head to penetrate the corona radiata and zona pellucida. It forms a tubelike structure known as the acrosomal apparatus that extends to and penetrates the membrane. Its pronucleus then may freely enter the oocyte once meiosis II has come to completion.
Cortical Reaction
release of calcium ions after the penetration of the sperm. The calcium ions depolarize the membrane of the ovum, which serves two purposes: prevents fertilization by multiple sperms. Also increases the metabolic rate of the newly formed zygote.
Fertilization membrane
Depolarizer, impenetrable membrane formed after the cortical reaction
Stages of development of the zygote to embryo?
Zygote, morula, blastula gastrula
Morula
Solid ball of cells after several divisions of the zygote
Blastula
Hollow ball of cells with a fluid filled inner cavity known as the blastocoel
What arises from the trophoblasts?
Chorion and later placenta
What are the two parts of the blastocyst?
Trophoblast and the inner cell mass (ICM).
In what stage is the embryo implanted in the uterine lining?
Blastula
Chorionic villi? What are they and what do they develop from?
Develop from the trophoblasts, and are fingerlike microscopic projections that penetrate the endometrium.
The 3 extraembryonic membranes?
Chorion, Amnion, and Allantois
Allantois?
Extraembryonic membrane that is involved in the fluid exchange between the yolk sac and the embryo.
Umbilical chord forms from what?
From yolk sac and Allantois.
Ectopic pregnancy
If the blastula implants itself outside the uterus. 95% in the Fallopian tube. Not viable, and if not self aborted, will rupture causing hemorrhage.
Name what you see if you move in from the uterine lining towards the embryo
Uterine lining, chorion, chorionic cavity, amnion, amniotic fluid, embryo.
Arcehnteron
Membrane invagination into the blastocoel during the formation of gastrula