What is the portal vein in the liver?
The portal vein (PV) is the main vessel of the PVS, resulting from the confluence of the splenic and superior mesenteric veins, and drains directly into the liver, contributing to approximately 75% of its blood flow [1]. Hepatic artery provides the remaining hepatic blood flow.
Is hypophyseal portal vein present in man?
There is another human portal venous system, the hypophyseal portal system, which transports hormones from the hypothalamus to the pituitary gland.
What vein transverses the liver?
Three large intrahepatic veins drain the liver parenchyma, into the inferior vena cava (IVC), and are named the right hepatic vein, middle hepatic vein and left hepatic vein. The veins are important landmarks, running in between and defining the segments of the liver.
What veins are part of the portal system?
The portal vein is formed by the union of the splenic vein and the superior mesenteric vein, posterior to the neck of the pancreas, at the level of L2. As it ascends towards the liver, the portal vein passes posteriorly to the superior part of the duodenum and the bile duct.
How many portal veins are there in human body?
It is a major component of the hepatic portal system, one of only two portal venous systems in the body – with the hypophyseal portal system being the other….
| Portal vein | |
|---|---|
| Drains from | Gastrointestinal tract, spleen, pancreas |
| Source | splenic vein, superior mesenteric vein, inferior mesenteric vein, pancreatic vein |
What is the hypophyseal portal vein?
The hypothalamic–hypophysial portal system is the conduit that connects the brain to the anterior pituitary. Blood coming from the capillary plexus of the median eminence is carried into a capillary bed in the anterior pituitary by long portal veins.
Does the portal vein drain the liver?
The blood leaves the liver to the heart in the hepatic veins. The portal vein is not a true vein, because it conducts blood to capillary beds in the liver and not directly to the heart….
| Portal vein | |
|---|---|
| Drains to | liver sinusoid |
| Identifiers | |
| Latin | vena portae hepatis |
| MeSH | D011169 |
What is the role of central vein in liver?
The central veins of liver (or central venules) are veins found at the center of hepatic lobules (one vein at each lobule center). They receive the blood mixed in the liver sinusoids and return it to circulation via the hepatic veins.
What is the difference between portal vein and normal vein?
Unlike most veins, the portal vein does not drain into the heart. Rather, it is part of a portal venous system that delivers venous blood into another capillary system, the hepatic sinusoids of the liver. After draining into the liver sinusoids, blood from the liver is drained by the hepatic vein.
Why is the hepatic portal vein called the portal vein?
Unqualified, portal venous system often refers to the hepatic portal system. For this reason, portal vein most commonly refers to the hepatic portal vein. The functional significance of such a system is that it transports products of one region directly to another region in relatively high concentrations.
Where does the hypophyseal vein drain blood from?
Hypophyseal veins drain blood from the anterior pituitary. The primary and secondary capillary plexuses in the pituitary gland, plus the intervening hypophyseal portal veins, constitute the hypophyseal portal system. Short veins from the pituitary gland drain into the neighboring dural venous sinuses. Figure 1. Hypophyseal portal system
How is the hypophyseal portal system related to the pituitary?
The hypophyseal portal system is a vascular system made of tiny blood vessels that connect the adenohypophysis to the hypothalamus. The capillaries and venules of the portal system are fenestrated which allows the smooth exchange of molecules between the blood vessels and the cells of the anterior pituitary.
Where does the portal venous system occur in the human body?
General diagram of a portal venous system, for example, this occurs in the hypophyseal portal system between the hypothalamus and the anterior pituitary gland. In the circulatory system of animals, a portal venous system occurs when a capillary bed pools into another capillary bed through veins, without first going through the heart.