Umbilical vein: Difference between revisions

| Name = Umbilical Veinvein

| Artery = [[umbilicalUmbilical artery]]

The '''umbilical vein''' is a [[vein]] present during [[fetal development]] that carries [[oxygenated blood]] from the [[placenta]] into the growing [[fetus]]. The umbilical vein provides convenient access to the central circulation of a neonate for restoration of blood volume and for administration of glucose and drugs.<ref name=":0" />

The blood pressure inside the umbilical vein is approximately 20 [[mmHg]].<ref>Wang, Y. Vascular biology of the placenta. in Colloquium Series on Integrated Systems Physiology: from Molecule to Function. 2010. Morgan & Claypool Life Sciences.</ref>

The unpaired umbilical vein carries oxygen and nutrient rich blood derived from fetal-maternal blood exchange at the [[chorionic villi]]. More than two-thirds of fetal hepatic circulation is via the main [[portal vein]], while the remainder is shunted from the left portal vein via the [[ductus venosus]] to the [[inferior vena cava]], eventually being delivered to the fetal [[right atrium]].

Within a week of birth, the neonate's umbilical vein is completely obliterated and is replaced by a fibrous cord called the [[Round ligament of liver|round ligament of the liver]] (also called ''{{Lang|la|ligamentum teres hepatis}}''). It extends from the umbilicus to the transverse fissure, where it joins with the [[falciform ligament of the liver]] to separate segment 4 from segments 2 and 3 of the left [[Lobe (anatomy)|hepatic lobe]].

Under extreme [[blood pressure|pressure]], the round ligament may reopen to allow the passage of blood. Such recanalization may be evident in patients with [[cirrhosis]] and [[portal hypertension]]. Patients with cirrhosis experience rapid growth of [[scar|scar tissue]] in and around the liver, often functionally obstructing nearby vessels. [[Vessel occlusion]] increases [[vascular resistance]] and therefore leads to hypertension. In portal hypertension, the vessels surrounding the [[liver]] are subjected to abnormally high blood pressure&mdash;so high, in fact, that the force of the blood pressing against the round ligament is sufficient to recanalize the structure. This leads to a condition called [[Caputcaput medusae]].{{Citation needed|reason=Recanalization is also claimed to be a myth(misinterpretation of enlargements of paraumbilical veins).|date=September 2020}}

A newborn baby has a patent umbilical vein for at least a week after birth. This umbilical vein may be catheterised for ready intravenous access. It may be used as a site for regular transfusion in cases of [[erythroblastosis]] or [[hemolytic disease]]. It also provides a route for measuring central venous pressure.<ref name=":0">{{Cite book|url=https://books.google.com/books/about/A_Practice_of_Anesthesia_for_Infants_and.html?id=iOqXLFBQt_UC|title=A Practice of Anesthesia for Infants and Children|lastlast1=Coté|firstfirst1=Charles J.|last2=Lerman|first2=Jerrold|last3=Todres|first3=I. David|date=2009|publisher=Elsevier Health Sciences|isbn=1416031340978-1416031345|language=en}}</ref>

ImageFile:Gray31.png|Model of human embryo, 1.3&nbsp;mm. long.

ImageFile:Gray39.png|Scheme of placental circulation.

ImageFile:Gray458.png|Diagram of the vascular channels in a human embryo of the second week.

ImageFile:Gray476.png|Human embryo with heart and anterior body-wall removed to show the [[sinus venosus]] and its tributaries.

ImageFile:Gray989.png|Schematic figure of the bursa[[lesser omentalissac]], etc. Human embryo of eight weeks.

ImageFile:Gray1088.png|Liver with the [[septum transversum]]. Human embryo, 3&nbsp;mm. long.

ImageFile:Gray1115.png|Tail end of human embryo, twenty-five to twenty-nine days old.

File:Umbilical vein.jpg|Umbilical vein

File:Slide1MINI.JPG|Human embryo, 38&nbsp;mm, 8–9 weeks.