Implantation Flashcards
Define gestational age.
Used to describe how far along the pregnancy is. Starts from the first day of the last menstrual cycle.
Define embryonic age.
This is the time from ovulation. It occurs up to 8 weeks, when the organs develop. After weeks is known as the fetal period.
What are pinopodes?
They are cellular outbranches from the surface of the endometrium, which allow attachment.
What is the role of enzymes COX-1 and COX-2?
They mediate the production of prostaglandins, to mediate blastocyst penetration of uterus.
What day is implantation completed?
Day 6/7.
What happens 3 days after fertilisation?
Cells of compacted embryo divide again → mulberry-shaped 16-cell morula (composed of two zones: inner, outer cell mass).
What is a blastocyst?
Structure formed in the early development of mammals. Fluid filled hollow cell, two zones.
What are the 2 zones of a blastocyst (day 2)? (day
Trophoblast: single layer of large flattened cells, stemming from morula’s outer cell mass; gives rise to placenta. Embryoblast: 20–30 pluripotent cells located on one side, stemming from inner cell mass; gives rise to embryo
What happens to the embryo 36 hours post fertilisation?
Series of fast mitotic divisions of zygote →increase number of cells, decrease size.
What arises from the Trophoblast?
Placenta.
What arises from the Embryoblast?
Embryo.
What produces the primary chorionic villi, which protrude the syncytiotrophoblast?
Cytotrophoblast.
Give 2 functions of the cells of the syncytiotrophoblast.
Penetrate the decidua basalis of the uterus. Penetrates maternal capillaries (sinusoids) so the embryo is surrounded by pool of leaked blood. Produces human chorionic hormone (hcG) - prevents corpus luteum apoptosis to produce progesterone.
Why is progesterone production important during implantation?
Prevents menstruation. Maintains endothelial lining of uterus.
The trophoblast differentiates into which 2 layers?
Syncytiotrophoblast. Cytotrophoblast.
