Early Embryology Flashcards
Where does fertilization take place?
Ampulla of the uterine tube
What processes must sperm undergo to be able to fertilize the egg?
Capacitation and acrosome
Female pronucleus
Formed after sperm has entered the egg via meiosis II of the oocyte’s nucleus
Male pronucleus
Formed by enlargement of the sperm’s nucleus
When and what is cleavage?
Occurs about 30 hrs post-fertilization, and is the cell division to form the blastocyst
Morula
when the cell have reached about 16-32 cells from division
What layers does the blastocyst separate into?
Embryo proper (inner cell mass) and Trophoblast (outer cell mass)
What portion of the trophoblast penetrates into the endothelium?
Syncyiotrophoblasts
Where is the extraembryonic mesoderm and what is it derived from?
Forms between the inner surface of the cytotrophoblast and outer surface of the amnion/exocoelomic membrane, and is derived from the umbilical vesicle
How is the chorionic cavity (extraembryonic cavity) formed?
Large cavities form in the extraembryonic mesoderm to form the cavity
What 2 layers does the extraembryonic mesoderm form?
Extraembryonic somatic mesoderm and extraembryonic splanchnic mesoderm
Hydatidiform Mole
Trophoblast forms placenta membranes, but no embryonic development. Secretes high levels of hCG and may become malignant. Most arise from fertilization of an oocyte with no nucleus
Placenta Previa
Placenta forms over the cervix, causing severe and possibly life-threatening bleeding later in pregnancy
Placenta percreta
Chorionic villi penetrate the myometrium all the way to the perimetrium
Placenta Accrete
Abnormal adherence of placenta to the myometrium
Ectopic pregnancy
Implantation of blastocyst outside of the uterus
Gastrulation
Process of establishing trilaminar germ disc. Cells slip underneath the epiblast forming the primitive streak
3 primary germ layers
ectoderm, mesoderm, endoderm