What is intervillous space?
What is intervillous space?
Definition. The intervillous space is normally filled with maternal blood and a small amount of fibrin, with the villi evenly spaced; neighboring villi usually do not touch one another. When fibrin entirely encases a villus, the villous syncytiotrophoblast covering gradually degenerates.
How is the intervillous space formed?
With this physiologic destructive process, the maternal blood vessels of the endometrium are opened, with the result that the spaces in the trophoblastic network are filled with maternal blood; these spaces communicate freely with one another and become greatly distended and form the intervillous space from which the …
What is the function of spiral arteries?
Spiral arteries are small arteries which temporarily supply blood to the endometrium of the uterus during the luteal phase of the menstrual cycle. In histology, identifying the presence of these arteries is one of the most useful techniques in identifying the phase of the cycle.
What happens to spiral arteries during menstruation?
The term “spiral arteries” reflects the coiled appearance of these vessels, whose role is to supply blood to the upper functional layer of the endometrium, thought to be shed during menstruation [95]. The spiral arteries branch into a subepithelial capillary plexus [95].
What is a Syncytiotrophoblast?
The syncytiotrophoblast, the outermost layer of the human placenta, is the main site of exchange for drugs and metabolites, nutrients, waste products, and gases between the maternal and fetal circulations.
What is chorionic plate?
The chorionic plate is a synonym for the fetal side of the placenta. The maternal side of the placenta is termed the basal plate. Some pathologies and processes are localized to the chorionic plate, and evaluation of the chorionic plate is a part of placental grading.
Why does the lining of the uterus have a good blood supply?
Endometrial arteries proliferate rapidly and react to different hormones released. These hormones are progesterone and estrogen released by the ovaries and produced by the endocrine system. The endometrial arteries not only supply blood to the endometrium but are also important during pregnancy.
What is Chorion mean?
: the highly vascular outer embryonic membrane of reptiles, birds, and mammals that in placental mammals is associated with the allantois in the formation of the placenta.
Where do spiral arteries come from?
Placental Anatomy and Transport. Maternal spiral arteries arise from the uterus and deposit oxygenated blood and nutrients into the intervillus space. The space is a cavernous expanse, into which the villous trees from the fetal circulation extend.
What happens to spiral arteries in preeclampsia?
During early human pregnancy extravillous cytotrophoblasts invade the uterus and spiral arteries transforming them into large vessels of low resistance. Failure of trophoblast invasion and spiral artery transformation occurs in preeclampsia and fetal growth restriction (FGR); these processes are not well understood.
Where are the spiral arteries located?
The spiral arteries are coiled towards the upper part of the endometrium and straight towards the base of the endometrium.
What is difference between cytotrophoblast and syncytiotrophoblast?
The syncytiotrophoblast is a rapidly growing multinucleated mass, which invades and ruptures endometrial capillaries forming lacunae. The cytotrophoblast is a layer of mononucleated cells, which invades the syncytiotrophoblast matrix and forms early chorionic villi.
What are the functions of the spiral artery?
In normal placental development, invasive cytotrophoblasts of fetal origin invade the maternal spiral arteries, transforming them from small-caliber resistance vessels to high-caliber capacitance vessels capable of providing placental perfusion adequate to sustain the growing fetus.
What happens if the spiral artery is failed?
Failure of trophoblast invasion of the spiral arteries results in increased vascular resistance of the uterine artery and decreased perfusion of the placenta, which may subsequently result in fetal growth restriction and/or preeclampsia18 (reviewed in Chapter 5).
Where does the maternal spiral artery come from?
Maternal spiral arteries arise from the uterus and deposit oxygenated blood and nutrients into the intervillus space. The space is a cavernous expanse, into which the villous trees from the fetal circulation extend.
Where are the trophoblasts located in the spiral artery?
These extravillous trophoblasts invade the maternal decidua and distal ends of the spiral arteries. Via complex interactions likely involving maternal decidua, glands, and immune cells, the interstitial trophoblasts migrate toward the spiral arteries, invade the arteries, and become endovascular trophoblasts.