The hepatic portal vein is formed by the union of the splenic vein and the_________. Select one: a. inferior mesenteric vein b. superior mesenteric vein c. renal vein d. gastric vein e. hepatic vein
The correct answer and explanation is:
The correct answer is b. superior mesenteric vein.
The hepatic portal vein is an important vessel in the circulatory system that carries blood from the digestive organs to the liver. It is formed by the union of two major veins: the splenic vein and the superior mesenteric vein. The purpose of this system is to direct blood from the stomach, intestines, spleen, and pancreas to the liver for filtration, processing, and detoxification.
The splenic vein drains blood from the spleen, parts of the stomach, and pancreas. The superior mesenteric vein carries blood from the small intestine, cecum, ascending colon, and part of the transverse colon. Together, these veins come together behind the pancreas to form the hepatic portal vein.
The hepatic portal vein does not carry oxygenated blood. Instead, it carries nutrient-rich, deoxygenated blood from the digestive organs to the liver. Once the blood reaches the liver, it passes through a series of capillaries called sinusoids, where the liver processes nutrients and detoxifies harmful substances. The liver cells (hepatocytes) regulate the levels of glucose, amino acids, and other nutrients. It also filters out toxins, such as drugs and alcohol, that may have been absorbed from the digestive tract. After this processing, the blood then exits the liver via the hepatic veins, which empty into the inferior vena cava, returning the blood to the heart.
This unique circulatory route is crucial because it allows the liver to control nutrient levels and prevent toxins from entering systemic circulation. The importance of the hepatic portal vein in maintaining metabolic balance and detoxification cannot be overstated.