Lecture B9 Flashcards
The placenta is the site of exchange for _____ and
contains tissues from _____
-nutrients, wastes, O2, and CO2 between the mother and the fetus
-both individuals
The major functions of the placenta are performed by _____
-trophoblast cells
Trophoblast cells are derived from the _____ of the early ____ and are the first ____ formed
-trophectoderm
-blastocyte
-extraembryonic lineage
problems with pregnancy, miscarriages, preeclampsia = _____
problems with trophoblasts
placenta forms ___ to increase SA of placenta
villi
Primary villi of placenta appear _____ after implantation as _____ covered by _____ extend into______ containing maternal blood.
-2 days
-simple cords of proliferating cytotrophoblast cells
-syncytiotrophoblast
-lacunae
Secondary villi begin to form on about the ____ of embryonic development as the primary villi are ______
-15th day
-invaded by extraembryonic mesenchyme
Tertiary villi develop within a _____ as mesenchyme in the secondary villi differentiates to form _____
-few more days
-capillary loops continuous with the embryonic circulatory system
By the end of the first month of the pregnancy, the placenta contains _____, each branching many times and each branch having _____
-thousands of tertiary chorionic villi
-one or more capillary loops
Exchange of gases, nutrients, and wastes occurs between fetal blood in the capillaries and maternal blood by bathing ______
-the villi, with diffusion occurring across the trophoblast layer and the capillary endothelium
To begin implantation, receptors on cells of the _______ bind glycoprotein ligands on the ______.
-outer embryonic trophoblast
-endometrial epithelium
The trophoblast forms an invasive, outer syncytial layer called the ______
-syncytiotrophoblast
The trophoblast differentiates during implantation into: ______
-cytotrophoblast (CT)
-syncytiotrophoblast (SCT)
cytotrophoblast (CT) descr.
-layer of undifferentiated mitotically active cells immediately around the amnion and yolk sac
CT cells synthesize _____ to prevent _____
-anti-inflammatory cytokines
-an adverse uterine reaction to the implanted embryo
Syncytiotrophoblast (SCT) descr.
-outer layer, nonmitotic mass of multinucleated cytoplasm that invades the surrounding stroma
-formed by fusion of CT cells
-In direct contact with maternal blood and mediate exchange of nutrients and gases
SCT cells produce ______
-hormones/factors needed for pregnancy maintenance
By about the ninth day after ovulation, the embryo is implanted in the endometrium
and derives _____. The endometrial stroma undergoes ______ in the period following implantation. _______ become enlarged, polygonal, more active in protein synthesis,
and are now called ______ .The whole endometrium is now called the ____
-nutrients primarily from blood there
-histologic changes
-Fibroblasts
-decidual cells
-decidua
ST is facing the ____ and turnover when?
-maternal blood
-throughout pregnancy
CT able to self renew or differentiate by _____
-fusing to form ST layer
vili tree formation is important for _____
exchnage of nutrients, wastes and gas
CT are always ____
actively fusing
ST is marked by expression of _____
chronic gonadotropin beta (tested in pregnancy)
CT is marked by expression of _____
e-cadherin (had tight junctions; lateral membrane)